Emerson Guide: EU-Energy-Efficiency-Directive-User-Guide-2013 Manuals & Guides

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Sustainable

Energy Efﬁciency

User Guide

Energy Efﬁciency in the Process Industries

A User-guide to Sustainable Energy Efﬁciency and the

Impact of the European Energy Efﬁciency Directive

Author: David Stockill

Contents

1 Introduction ..................................................................................................10

1.1 Preface ............................................................................................................................................10

1.2 Intended Audience ..........................................................................................................................10

1.3 How to use the Guide .....................................................................................................................11

2 Deﬁnitions, Acronyms and Terminology .....................................................12

The concept of Industrial Energy Distribution: ...............................................................................12

3 Energy Efﬁciency Challenges in 2013 ........................................................15

3.1 Background ....................................................................................................................................15

3.2 Process Industry Potential ..............................................................................................................17

3.3 The 2012 Energy Efﬁciency Directive .............................................................................................17

4 Developing the Way Forward.......................................................................18

4.1 The Overall Programme ..................................................................................................................18

4.2 Assessment of Site Energy Maturity - the Initial Health Check ......................................................20

4.3 Energy Programme Skills and Resources .....................................................................................21

5 Core Operation – The Energy Management System ..................................23

5.1 Developing an EMS ........................................................................................................................23

5.1.1 The EMS Design Workshop ...........................................................................................................24

5.1.1.1 Timing and organisation .................................................................................................................24

5.1.1.2 Attendees ........................................................................................................................................24

5.1.1.3 Agenda ............................................................................................................................................24

5.1.1.4 Outcomes........................................................................................................................................25

5.1.2 Basic Components of EMS – ‘Essential Best Practice’ ..................................................................25

5.1.2.1 Policy and Strategy .........................................................................................................................25

5.1.2.2 Accountabilities ...............................................................................................................................27

5.1.2.3 Organisation....................................................................................................................................27

5.1.2.4 Competencies .................................................................................................................................27

5.1.2.5 Work Processes ..............................................................................................................................28

5.2 ISO 50001 .......................................................................................................................................28

5.2.1 Plan-Do-Check-Act..........................................................................................................................30

5.2.2 Beneﬁts of Certiﬁcation ...................................................................................................................31

5.3 Links to Corporate Systems ...........................................................................................................31

5.4 Development Support and further Information ..............................................................................31

Contents

6 Energy Management Information Systems .................................................32

6.1 Objectives .......................................................................................................................................32

6.2 The Components of EMIS ..............................................................................................................33

6.2.1 System conﬁguration – hardware/software ....................................................................................33

6.2.2 Data Structures/KPI and Target Setting Philosophy .......................................................................34

6.2.3 Energy Driver Variables ..................................................................................................................36

6.2.4 Use of Energy Loss Points ..............................................................................................................36

6.3 Operating with EMIS & User Interfaces ..........................................................................................37

6.3.1 User Interfaces ................................................................................................................................38

6.4 Development of an EMIS ................................................................................................................42

6.5 Core Activities - System Building....................................................................................................42

6.5.1 Allocate Areas of Operation ............................................................................................................42

Feedstocks ......................................................................................................................................43

Products ..........................................................................................................................................43

Classes of Energy ...........................................................................................................................43

6.5.2 Energy balances .............................................................................................................................44

6.5.3 Identiﬁcation of Energy Loss Points ...............................................................................................45

6.5.4 Preliminary list of KPIs ....................................................................................................................45

6.5.5 Driver Development and Identiﬁcation ...........................................................................................45

6.5.6 Constraint identiﬁcation ..................................................................................................................46

6.5.7 Setting Targets for KPIs and Drivers ..............................................................................................46

6.5.7.1 Historical Best performance ...........................................................................................................46

6.5.7.2 Statistical Correlation ......................................................................................................................47

6.5.7.3 First Principles Model .....................................................................................................................47

6.5.8 Data Validation ................................................................................................................................48

6.6 EMIS Skills and Competencies ......................................................................................................48

6.7 Key EMS Applications and Processes ...........................................................................................48

7 Energy Target Setting and Performance Review ........................................49

7.1 The Energy Target Setting Process ................................................................................................50

7.1.1 Site Energy Monitoring Targets and KPI Structure .........................................................................50

7.1.2 Annual Target Setting ......................................................................................................................50

7.1.3 Monthly Target Setting ....................................................................................................................51

7.1.4 Weekly Operational Targets and the setting of Operating Instructions .........................................51

7.1.5 Daily and Real-time activities ..........................................................................................................51

7.2 The Energy Performance Review Process .....................................................................................51

7.2.1 Daily Energy Performance Review .................................................................................................51

7.2.2 Weekly Energy Performance Review ..............................................................................................52

7.2.3 Monthly Site Energy Performance Review .....................................................................................52

Contents

8 The Impact of Maintenance Practices on

Energy Performance ....................................................................................

9 Making a Step-change: Opportunities, Auditing

and Improvement Projects ..........................................................................

9.1 The Energy Walkthrough ................................................................................................................57

9.2 Energy Projects – Identiﬁcation and Assessment ..........................................................................57

9.2.1 Team and Preparation .....................................................................................................................58

9.2.2 Assessment Process and Operational Reviews .............................................................................58

9.2.3 Project Generation and Validation ..................................................................................................59

9.3 Ongoing Improvement – The Mature Operation ............................................................................59

9.4 Financial Planning and Project Economics ....................................................................................60

9.4.1 Standard Project Economics Techniques ......................................................................................60

9.4.2 Utilities Marginal pricing .................................................................................................................62

9.4.3 Investment Thresholds for Energy Projects ...................................................................................63

10 Common Energy Tools and Techniques .....................................................64

10.1 Measurement and Control of Energy Streams ...............................................................................64

10.1.1 Mass and Energy Balances ............................................................................................................64

10.1.1.1 Feed and Product streams .............................................................................................................65

10.1.1.2 Steam ..............................................................................................................................................65

10.1.1.3 Fuels ................................................................................................................................................65

10.1.1.4 Electrical Power Measurements .....................................................................................................66

10.1.2 Process Control ..............................................................................................................................66

10.1.2.1 Controller Tuning and Basic Set-up. ...............................................................................................66

10.1.2.2 Feed-Forward Control .....................................................................................................................67

10.1.2.3 Constraint pushing control .............................................................................................................68

10.1.2.4 Model Predictive Control (MPC) .....................................................................................................69

10.2 Utilities Systems ..............................................................................................................................71

10.2.1 Steam Generation ...........................................................................................................................71

10.2.1.1 Boiler Feed Water Preheat .............................................................................................................71

10.2.1.2 Deaerator operation ........................................................................................................................72

10.2.1.3 Minimising Blowdown .....................................................................................................................73

10.2.1.4 Condensate Collection and Heat Recovery ...................................................................................74

10.2.2 Steam Networks and Distribution Optimisation .............................................................................74

10.2.2.1 Utilities Optimisation ......................................................................................................................75

10.2.2.2 Structural changes - Steam blending .............................................................................................76

10.3 Combustion Activities .....................................................................................................................76

10.3.1 Installed Equipment ........................................................................................................................77

10.3.1.1 Upgrade natural draught to forced draught operation...................................................................77

10.3.1.2 Improved combustion air-preheat ..................................................................................................77

10.3.1.3 Burner upgrades – low NO

10.3.2 Furnace Control ..............................................................................................................................78

and turndown ....................................................................................78

Contents

10.3.2.1 Air and Fuel Measurement ..............................................................................................................78

10.3.2.2 Air-Fuel ratio control ........................................................................................................................78

10.3.2.3 Waste Gas Firing .............................................................................................................................79

10.3.3 Furnace Operations – Training and Competencies .......................................................................80

10.3.4 Maintaining Fired Equipment .........................................................................................................81

10.4 Maintenance in Support of Energy Efﬁciency ................................................................................81

10.4.1 Cleaning of Heat Transfer Equipment (including ﬁn-fans) .............................................................82

10.4.2 Steam Leak Programmes ..............................................................................................................82

‘Steam Team’ example....................................................................................................................82

Steam Trap Monitoring ...................................................................................................................83

10.4.4 Lagging ...........................................................................................................................................84

10.4.5 Use of Asset Monitoring Techniques ..............................................................................................85

10.5 Pinch Analysis and Improved Heat Recovery ................................................................................86

10.5.1 Pinch Analysis .................................................................................................................................86

10.6 Variable Speed Drives.....................................................................................................................88

11 Skills and Competencies for Energy Activities ..........................................89

11.1 Organisational Core Competencies and Skill Areas ......................................................................89

11.1.1 Site Energy Manager ......................................................................................................................89

11.1.2 Process Engineers ..........................................................................................................................89

11.1.3 Utilities Engineering ........................................................................................................................90

11.1.4 Control and Instrumentation ...........................................................................................................90

11.1.5 Operational Staff .............................................................................................................................90

11.2 Important Specialist Support Skills ................................................................................................90

11.3 EMS and EMIS skills and competencies ........................................................................................91

11.4 Skill Management ...........................................................................................................................92

12 The EU Energy Efﬁciency Directive.............................................................93

12.1 History and Development ...............................................................................................................93

12.2 Highlights ........................................................................................................................................93

12.3 Main recommendations for the Process Industries .......................................................................94

12.3.1 Energy Audits ..................................................................................................................................94

12.3.1.1 Requirements to undergo auditing .................................................................................................94

12.3.1.2 Auditing and Energy Management Systems Exemption ...............................................................95

12.3.1.3 Requirements on SMEs ..................................................................................................................95

12.3.1.4 Minimum Audit Standards ..............................................................................................................95

12.3.2 Energy Targets and Obligation Schemes .......................................................................................96

12.3.2.1 Requirements on Member States ..................................................................................................96

12.3.2.2 Sectors to be included/excluded ....................................................................................................96

12.3.2.3 Alternate Policy Measures ..............................................................................................................96

12.4 How will it be managed? How does the EED apply to you?..........................................................97

Contents

13 Beneﬁts and Case Studies ..........................................................................98

13.1 The Beneﬁts from Energy Management Systems ..........................................................................98

13.2 Case study 1 – Performance Modelling and Measurement ...........................................................99

13.3 Case study 2 – the Role of Maintenance and Management ..........................................................99

Supporting Appendices ........................................................................................... 101

Appendix A. ISO 50001 ............................................................................................ 102

A.1 Structure........................................................................................................................................102

A.2 Methodology .................................................................................................................................102

A.3 Implementing ISO 50001 ..............................................................................................................103

A.4 Contents of ISO 50001 .................................................................................................................104

Appendix B. Carbon Trust

Energy Management Maturity Matrix ......................................................................

105

Appendix C. EMIS Objectives checklist ................................................................. 106

C.1 Functionality: Does the EMIS Deliver the Following? ...................................................................106

C.2 Features: Does the EMIS Include the Following Key Features? ..................................................107

C.3 System Components ....................................................................................................................108

C.4 EMIS Support ................................................................................................................................109

Appendix D. Energy Walkthrough Template ........................................................... 110

D.1 Team Composition ........................................................................................................................ 110

D.2 Pre-Walkthrough Information to be provided by the Site .............................................................110

D.3 Site Operational Overview ............................................................................................................111

D.4 Site-Wide Energy Management Questionnaire ............................................................................ 112

D.5 Typical Process Unit Interview .....................................................................................................113

D.6 Energy Management Maturity Assessment..................................................................................114

D.7 Inventorise and prioritise opportunities for improvement ............................................................114

Contents

Appendix E. Energy Projects –

Identiﬁcation and Assessment Process..................................................................

E.1 Preparation....................................................................................................................................115

E.1.1 Information review.........................................................................................................................115

E.1.2 Plan for Assessment Period ..........................................................................................................116

E.1.3 Develop Understanding of Plant Conﬁguration and Energy Use ................................................116

E.1.4 Operations Reviews .....................................................................................................................116

E.2 Generate Observations and Opportunities ..................................................................................117

E.2.1 Observations .................................................................................................................................117

E.2.2 Creating Opportunities .................................................................................................................118

E.2.3 Opportunities Validation ...............................................................................................................119

E.2.4 Opportunities Prioritisation and Project Development .................................................................119

E.2.5 Early Implementation (Quick-win) ................................................................................................119

E.3 Example of Observations-Gathering Datasheet ...........................................................................120

E.4 Example of Opportunity Data Base ..............................................................................................122

Potential Opportunities – Project Masterlist XYZ Company at Location ABC .............................122

E.5 Energy Improvement Proposal Template ....................................................................................123

E.5 Energy Improvement Proposal Template (continued) .................................................................124

115

Appendix F. Emerson Process Management Tools

and techniques web links ........................................................................................

125

Appendix G. EU BReF Listing .................................................................................. 126

Appendix H. Other Good Practice Guides

and sources of Information ....................................................................................

127

Introduction

1 Introduction

1.1 Preface

The EU Energy Efﬁciency Directive 2011/172 (referred to as the EED) came into force in November 2012 and will be rolled out across EU Member States during 2013/14. Whilst the EED covers a complete spectrum of activities, from domestic energy usage through buildings, transport, distribution and Industry, the key issues relevant to the Process Industry sector are the encouragement to implement energy management systems and also the requirement for large industrial plants to undergo regular energy performance audits by externally accredited auditors. The EED speciﬁcally mandates the encouragement of SMEs to adopt Best Practice in these areas.

Minimum requirements are speciﬁed in the EED to form the basis for Member States to develop their legislation and local standards.

This manual has been expressly developed with the EED standards in mind and is designed to present a Best Practice methodology for Process Industry Users which is consistent with and more than meets the requirements of the EED.

1.2 Intended Audience

This guide has two prime readerships:

Firstly, Operations and Technology Managers who wish to understand the impact of the Energy Efﬁciency Directive and how current Best Practice can be put to use to develop a sustainable plan leading to long term energy efﬁcient operation. It will also be of use to Corporate Energy Managers who are looking at developing a company-wide energy strategy.

Secondly, it is targeted at Energy Managers and Engineers who have been charged with bringing such a programme into reality and need a framework around which to develop the detailed Site initiatives, activities and projects.

In developing this guide a mental model of a typical mid-range process or chemical site has been used. This will have a traditional well-known organisational structure – Site Management Team, Operations Department (perhaps several plants), Maintenance Department (perhaps a few zones), Technical Support, Finance, HR, IT etc. This may or may not apply to the reader’s particular circumstances but it is hoped to be a recognisable entity and that the reader can draw parallels with his/her own Site and organisation.

Introduction

1.3 How to use the Guide

The guide is not intended as a deﬁnitive recipe book. Local circumstances, business types and organisations will have a large inﬂuence in the actual practice employed. However the Guide should enable a Company or location to determine a credible framework in which to operate.

Chapters 4 to 8 form the core of the Guide – Assessing the energy issues on Site, developing an Energy Management System, Building an Energy Management Information system and running Audits and Improvement programmes. These can be read as a complete picture, particularly useful if the reader is coming from a site with no existing energy management structures in place. However the individual chapters are designed as far as possible to be stand-alone in their own right and can be read as such.

Alongside this are supporting chapters on energy efﬁciency techniques, ﬁnancial beneﬁts, case studies, the impact of the European Energy Directive and various detailed Appendices.

Energy Management

Processes

Chapter 7

Determine

the Plan

Chapter 4

Develop Energy

Management System

Chapter 5

Energy Management

Info Systems

Chapter 6

Energy Improvement Programs & Projects

Chapter 8

Secondary Energy

Losses in Final UseLosses in Transformation

Process Heat

Direct Heat

Motive Force

Illumination

Others

Primary Energy

Transformation

Process

Final Use

Useful Energy

Final Energy

Definitions, Acronyms and Terminology

2 Deﬁnitions, Acronyms and Terminology

The concept of Industrial Energy Distribution:

BReF Best Available Technology Reference Documents. Best practice

documents prepared under the IPPC.

Carbon Trust A non-proﬁt company, established by the UK Government, that helps organisations reduce their carbon emissions and become more resource efﬁcient. Its stated mission is to accelerate the move to a sustainable, low carbon economy & reinvests surpluses from its commercial activities to this aim.

Class of Energy A generic descriptor for different types of energy used in manufacturing – fuel gas, electricity, steam, etc.

DCS Distributed Control System. The generic name for a typical microprocessor-based control system used to control the production line in the process industries. The entire system of controllers is connected by networks for communication and monitoring.

EED Energy Efﬁciency Directive. Issued in 2012, the EED is a more stringent set of targets and legislation behind a more harmonised EU Energy Policy.

EII Energy Intensity Index. A benchmarking index, widely used in the Oil Reﬁning Industry, which allows comparison for energy performance between sites and companies. Fundamentally an energy/feed ratio with many industry-speciﬁc corrections.

Definitions, Acronyms and Terminology

EMS Energy Management System. A documented system of work processes which deﬁnes how a particular location will manage energy in an efﬁcient manner (strategy, responsibilities, actions, checks).

EMIS Energy Management Information System. The data storage and reporting system, typically part of the Process Historian, which provides energy data, calculations, reporting and the foundation for energy consumption analysis.

ETS Emissions Trading System. Established by the EU in 2005, the ETS is a market-based approach using cap and trade methods to control greenhouse gases by providing economic incentives for achieving reductions in the emissions.

Energy Drivers The plant variables (ﬂows, temperatures) which have a direct impact on the energy consumption of a particular unit.

Energy Project Assessment A detailed assessment of a unit energy performance leading to a set of costed and prioritised project recommendations

Energy Walkthrough A short assessment of a location’s energy strategy, performance and outline scope for improvement.

HPS High Pressure Steam. Typically the highest pressure level steam generated in the Boiler House on a manufacturing complex. Normally used for electricity generation in turbo-alternator sets.

IED Industrial Emissions Directive. 2010 Directive replacing the IPPC and other related directives in a single updated document.

IPPC Integrated Pollution Prevention and Control. 1996 EU directive, updated in 2008 deﬁning the pollution control obligations with which industrial activities must comply. It establishes a procedure for authorising these activities and sets minimum requirements to be included in all permits, particularly in terms of pollutants released.

ISO 50001 The International Standard for Energy Management Systems.

ISO 14001 The International Standard for Environmental Management Systems.

KPI Key Performance Indicator. A calculated measure of performance for

comparison and benchmarking purposes, e.g. tonnes fuel/tonne feed processed.

LC(C)A Life Cycle (Cost) Analysis. Economic project evaluation techniques which look to total costs and beneﬁts and their phasing over the installed life of a project investment.

LHV Lower Heating Value. The effective sensible heat available from a combustible fuel.

LPS Low Pressure Steam. The lowest pressure steam on site – produced as let-down from MPS consumers. Used for all general steam utilities, tracing, low temperature process users.

Definitions, Acronyms and Terminology

MPS Medium Pressure Steam. Often produced as the let-down steam from electricity generation, MPS is used typically for drives, ejectors, and key processes uses needing a high steam condensing temperature.

Pinch Analysis A methodology for minimising energy consumption of process units by calculating thermodynamically feasible energy targets and achieving them by optimising heat recovery systems, energy supply methods and process operating conditions.

Plan-Do-Check-Act The basic stages in the ISO series of Management Systems.

Primary Energy Conversion The initial transformation of external fuels into energy streams, either

directly to the process or in a boiler house/utilities complex.

Process Historian A long term storage vehicle for process data (ﬂows, temperatures), often integrated into the DCS. Allows easy data retrieval, report building and calculations and programming using historical plant data. Nowadays accessed through Window/PC applications

SCADA Supervisory Control And Data Acquisition. A form of computer control typically used for multiple sites and remote locations.

Secondary Energy Conversion The subsequent utilisation of energy already transformed into steam and electricity by the process.

SME Small & Medium Enterprises. Deﬁned as <250 employees and <€50 million turnover

Stoichiometric combustion The theoretical point at which exactly enough combustion air is provided to burn a given quantity of fuel. Below this point, partial or incomplete combustion takes place.

Utilities systems The generic term for the collection of plants, normally boilers and power generators, which provide site-wide common energy steams steam, electricity, nitrogen, compressed air etc. for subsequent use by the processing units.

Wireless technology In this instance the use of wireless technology to communicate between ﬁeld instrumentation devices and control rooms, replacing the conventional 4 – 20mA wiring systems.

2020 Targets The EU targets on renewable and energy efﬁciency originally announced in 2007.

Energy Efficiency Challenges in 2013

3 Energy Efﬁciency Challenges in 2013

3.1 Background

Energy saving initiatives in the Process Industry have had a chequered history. A regular part of industrial life, especially since the end of ‘cheap oil’ in the mid 1970s, the tools and techniques are well known and can generate an attractive earning power. But Industry has not moved on to new higher levels of Energy Efﬁciency. Universal feedback from suppliers and customers points to issues surrounding the long term sustainability of energy improvement programmes. Beneﬁts erosion is common. Yet in simple terms energy saving appears attractive – solid, understandable technology and good payback.

How does this come about?

Whilst single large capex items can make a structural change in energy performance (e.g. installation of a co-gen unit) a plant’s energy performance is generally driven by a large set of (sometimes conﬂicting) factors:

• Adherence to Operational targets

• Maintenance activities (equipment efﬁciency and reliability)

• Employed Technology

• Design standards

• Culture and Competency

• Balancing yield/margin/energy

There is no single factor that ‘sets’ energy. Operating environments continually change. Energy efﬁcient operation requires continual attention to all these factors. As a result, energy has often “slipped through the gaps” and has deteriorated at the expense of short term gains and budgetary pressures. This was not helped by low energy prices in the early 2000s. Priorities were elsewhere.

There is no magic ‘silver bullet’. Sustainable Energy Efﬁciency requires a combination of technology plus procedural and housekeeping approaches and is being encapsulated in the new Standards on Energy and CO

Management (e.g. ISO 50001). Detailed point solutions are typically simple and well known but the

overall management is a more complex picture.

Fundamentally it is a control problem; at management level – using process data to analyse performance and drive improvement, and at operational level – using modern control techniques to operate closer to (energy efﬁcient) constraints. Accurate, reliable plant energy measurements plus a Distributed Control System and Process Historian provide the foundation to build a consistent approach to energy management.

Energy Efficiency Challenges in 2013

Improvement Programme

Increased Margin

Management Systems

Benchmarking

Industrial Best Practise

Energy

Management

Process

Reduction

Reduced Environmental Impact

This must be complemented by Systematic Management to ensure long term sustainability and drive Improvement. This sets the entire corporate framework in which the differing levels of control operate. ISO 50001 speciﬁes requirements for an organisation to establish, implement, maintain and improve an Energy Management System. It applies to all aspects affecting energy use which can be monitored and inﬂuenced by an organisation.

The key approach is adopting a ﬁt-for-purpose vision which deﬁnes the aims and provides the basic checks on management commitment and organisation together with a step-by-step approach to operational improvement.

• Review current Energy Management Effectiveness

• Deﬁne Management Responsibilities

• Develop Simple Performance Review

• Identify and Implement initial low level applications. Quick wins

• Review and Improve

The picture emerges of high quality process energy measurements, archived in a site-wide process historian, accessed through user-oriented (PC) interfaces. Modern control, modelling and data analysis tools utilise this data. New measurement techniques (e.g. wireless technology) allow easy access to energy variables which were traditionally excluded from plant instrumentation. Surrounding this is a formalised management process which determines the accountabilities and processes to ensure continuous performance appraisal and improvement.

This then provides the environment for sustainable energy projects and improvement programmes. Audits, plant assessments, opportunity developments and capital projects can proceed with a foundation that will address the ongoing support and assessment needed to ensure continual generation of beneﬁts.

Energy Efficiency Challenges in 2013

3.2 Process Industry Potential

In a future of uncertain energy supplies, volatile prices and continuing focus on CO2 emissions, managing the efﬁcient energy consumption of Industrial plants has to become an important ‘must do’ activity. This complexity and uncertainty means that Carbon, climate change and energy efﬁciency are becoming important Board level issues with key impacts on competitiveness, product strategies, brand and reputation. It can be foreseen that Industrial attitudes to Energy Efﬁciency could be transformed in a similar way to that of Health and Safety.

Industrial Energy Efﬁciency is inﬂuenced by a wide variety of factors in all aspects of operation – technology, maintenance activities, operational excellence, design, skills, competencies and training. Whilst industry has undertaken a variety of energy saving initiatives over many years they have shown varied success and, historically, problems of sustainability have been reported. Efﬁciency gains have failed to be sustained as long term energy savings. This is a reﬂection of the complexity of this multifaceted problem and an inconsistent historical focus on energy in the light of varying energy costs and shifting industrial priorities over time.

Fundamentally, to successfully maintain long term energy savings, it is necessary to address the core issues of energy strategy and management within an industrial organisation. The priorities need to be raised and energy issues embedded across all levels of an organisation. Are the accountabilities, processes and practices in place to ensure the long term realisation of the energy saving initiatives? These provide the backbone to the successful realisation of technological improvements.

3.3 The 2012 Energy Efﬁciency Directive

The European Union has recognised that without further action the EU ‘2020’ targets* are looking increasingly difﬁcult to achieve. For companies covered by the EUETS Carbon Trading scheme there can still be a gulf between the trade in Carbon credits and the actual day-to-day operation out on the plant. Accordingly the new Energy Efﬁciency Directive (EED) has been agreed to provide a stronger legislative framework to drive Industry towards greater energy efﬁciency and is focussed more directly at the operational level. Whilst the EED has to address a full range of energy-related business and activities, from domestic energy usage through buildings, transport, distribution it is possible to consider the impacts on the Process Industry which is typiﬁed by high energy chemical processing plants. The key issues relevant to the Process Industry sector are the encouragement to implement energy management systems and also the requirement for large industrial plants to undergo regular energy performance audits by externally accredited auditors. The EED speciﬁcally mandates the encouragement of SMEs to adopt Best Practice in these areas.

Minimum requirements are speciﬁed in the EED to form the basis for Member States to develop their legislation and local standards. This manual has been expressly developed with the EED standards in mind and is designed to present a Best Practice methodology which is consistent with and more than meets the requirements of the EED.

*20% reduction in Greenhouse Gas Emissions, 20% of Energy from Renewables, 20% reduction in Energy Consumption.

Developing the Way Forward

4 Developing the Way Forward

Traditional Energy Improvement projects have concentrated on the technology – typically some form of energy audit/opportunity identiﬁcation coupled with a project implementation. Perhaps run as a turnkey project. As has been discussed, there have been issues with continued operation and sustaining long term energy savings. It can be treated as a solution in isolation and the more complex issues in the operational environment that surround the application are not addressed. Focus can be lost. Similarly, auditing and energy project identiﬁcation can be a sterile activity producing a ‘shopping list’ of projects which stand little chance of successful realisation if there is no clear strategy, organisation and commitment to seeing them through.

Thus when a process

Improvement Opportunities

& Projects

Technical Audit,

Best Practice & Innovation

plant or company embarks on a programme aimed at improving its energy efﬁciency performance a wider picture has to be addressed for these and other reasons already outlined in section 3. Best practice, technology and projects need to be exploited in an environment which addresses the company energy strategy and ensures that all the supporting elements of that strategy – the Energy Management System – are in place. Without this approach there is a clear risk that well-earned efﬁciency gains and can fade and efﬁciency opportunities are not picked up. The EED recognises this and promotes both technical auditing and opportunity identiﬁcation as well as supporting the introduction of Energy Management Systems.

Aim:

Improve Energy

EED

Impacts

Management

Systems and

Performance Review

Result:

Long Term Sustained

Efficiency

Strategy, Culture &

Operations

These complementary issues will be picked up in the forthcoming chapters.

4.1 The Overall Programme

The scenario that will now be presented assumes the case of a typical manufacturing site that wishes to establish a sustainable energy efﬁciency programme. This may have been driven by one of several reasons – some competitive benchmarking, a corporate initiative, an analysis of operating costs which highlighted energy costs or something as simple as a new manager bringing in external experience. Anyway the site wishes to embark on an Energy Improvement Initiative. Of course all sites are different and some may be driven by certain dominant considerations – a constrained utilities network, a particular fuel supply, local emissions regulations etc. The speciﬁc detailed solutions to those are beyond the scope of this work however the overall approach to the Improvement programme is common to all and sets the scene from which to tackle the local issues.

Developing the Way Forward

In general the programme will be built around the following basic elements:

• Capital Investment on energy saving technology

• Plant change and operational excellence items

• Systems for Energy Management (strategies, organisation, processes, competencies)

• Energy Reporting and Analysis tools (metrics, targets, reports, etc)

Depending on the maturity of the Site more or less of these may be in place or partly developed.

The aim of the exercise is to establish the correct foundation of management systems and supporting tools which then enables improvement and investment programmes and activities to be developed and executed in a sustainable and proﬁtable manner. All carried out under an agreed clear strategy and vision for site energy performance.

The overall process is as follows:

1. Assess Site’s Energy Performance and Priorities

2. Develop Strategy

3. Develop Management Systems and Tools

4. Kick-off Energy Improvement Audit, identify projects and implement

• Technology

Energy

Strategy

• Operations

• Maintenance

• People

Develop

Programme

Assess Site

Maturity

Design

Workshop

KPIs

Work

Processes

Energy Performance Management

Continuous

Improvement

Tools, Projects & Programmes

Ideally, a full improvement process and project roll-out programme should materialise as a natural consequence of the EMS and strategy, however it can be desirable to start a ‘quick wins’ programme of projects at an early stage to gain results momentum and buy–in from good speedy successes.

Developing the Way Forward

4.2 Assessment of Site Energy Maturity - the Initial Health Check

In developing the energy programme a key ﬁrst step is an initial assessment of the energy priorities and also the maturity of a manufacturing site’s energy management. Typically a short (2 – 3 day) walkthrough exercise by an experienced energy management specialist can sufﬁce. This will be used to shape the roll-out and priorities of the Programme.

Inputs to this process will be:

• Interviews with key management and operational staff

• Benchmarking and historical performance data

• Review of future energy constraints, external business drivers and expected impacts

• Completion of maturity assessment (e.g. Carbon Trust model)

The aim is to understand the site’s energy maturity and be able to design and shape the programme. A typical health check Assessment agenda and data request form is given in Appendix B.

Outputs of the Assessment will be:

• Understanding of key energy issues and opportunities facing the site

• Basic map of energy utilisation across the site

• Understanding of constraints and drivers affecting future energy efﬁciency strategy

• Extent of, and strengths and weaknesses of the site’s current Energy Management processes

This should be in sufﬁcient detail so as to be able to design an outline Improvement programme and, importantly, scope the Design Workshop so as to best reﬂect the key site situation.

The Maturity Assessment is a powerful tool in understanding how advanced a site’s strategic and organisational attitudes are towards energy management. Various models are available although most are variations on the same basic theme. Examples include the Carbon Trust model (1) and also the Energy Star Plant Managers Guide (2). Appendix B shows the Carbon Trust maturity matrix. The results of the Assessment will play an important role in determining the Improvement Programme priorities and also the design/evaluation of the Site Energy Management System (see section 5.2).

Both guides give more comprehensive guidance on how to use the assessment methodology and develop the Programmes.

1) Good Practice Guide: A Strategic Approach to Energy & Environmental Management. The Carbon Trust, GPG376.

2) An Energy Star Guide for Energy & Plant Managers. Berkeley National Laboratory, LBNL-56183.

Developing the Way Forward

4.3 Energy Programme Skills and Resources

Two positions are essential to any Energy Improvement Programme: a sponsor on the site Management Team and a (full-time) Programme Manager. These will lead an implementation activity (full-time or part-time) supported by specialist resources on an as-needs basis. Beyond the implementation programme the position of Site Energy Manager is a key long-term requirement.

The Management Team representation is vital to ensure that the inevitable cross-departmental issues and priorities that any energy programme inevitably raises are resolved at the right level. It also promotes the correct gravitas and commitment to the programme and should be maintained in the long term as a permanent responsibility (e.g. refer to Maturity Assessment Matrix in Appendix B).

The Programme Manager’s role is to run the programme on a day-to-day basis and deliver the changes. Whether this is a single role or running a team on a larger project will vary depending on the scale of activities.

Implementation Team Core skills:

• Process Engineering

• Operations Management awareness - how does the site operate, understanding the responsibilities, information ﬂows with lines of communication and delegation

• Basic Control and Instrumentation knowledge

• Appreciation of business economics and scheduling

• Programme management, project planning

Specialist areas (access on an as-needs basis):

• Utilities engineering

• Process Specialists

• Combustion design and operation

• Heat transfer (e.g. Pinch technology)

• Power generation

• Compressed Air

• Turbine specialist

• Advanced control and optimisation

• Measurement specialist

• Process and Statistical modelling

Operations Team Representative

Particularly on larger projects an Operations Team Representative is an important role. Perhaps a training foreman or a day operator he/she can impart vital local operational knowledge and act as a guide and conduit for communications between the energy team and the plant.

Developing the Way Forward

Site Energy Manager

All organisations should have an Energy Manager or focal point as a permanent position with the following key responsibilities:

• Site performance monitoring and communications

• Owner of site energy data and records

• Initiation and tracking of energy improvement programmes and initiatives

• Technology and good practice gate-keeping

• Site Energy liaison to external bodies (corporate, institutions)

• Owner of ISO 50001/EMS system

This position should be sufﬁciently senior in the organisation to be able to communicate with and inﬂuence plant and departmental managers. There should be a clear link through to the Site Management Team representative.

Strategy

Core Operation – The Energy Management System

5 Core Operation – The Energy Management System

Energy Management forms the framework for an Organisation’s energy decision making – it is the glue that provides consistency and focus to this multifaceted problem which otherwise can prove difﬁcult to address by normal operational structures. In developing an EMS the most important consideration is that it should be ‘ﬁt for purpose’. There is no one-size-ﬁts-all. It must be a reﬂection of the facilities, priorities, strategy and culture of the site or company in question.

In essence an Energy Management System is a documented description of how energy is managed at that location/company. It includes strategy, accountabilities, processes to be followed and means of checking that the processes are adhered to. Typically it may follow the well-known Plan-Do-Check-Act philosophy that is encapsulated in the various ISO management models. Generally a set of tools and reports of energy and related parameters (the Energy Management Information System) support the management process (e.g. providing speciﬁc energy consumption data for performance review).

The following chapters provide guidance in establishing an Energy Management Strategy and Energy Management Information System (EMIS). ISO 50001, the International Standard on Energy Management, can provide a useful framework for such developments and this is addressed in section 5.2. Accreditation to ISO 50001 also provides the compliance discipline and external recognition that some organisations may require. But this is by no means a mandatory step.

5.1 Developing an EMS

The prime elements in developing an EMS are:

1. Understanding how Energy is currently managed

2. Developing an agreed vision of how energy will be managed in the future

3. Determining the actions to get there – deﬁning the processes

4. Execution

Accountabilities

Organisation

Competencies

Work Processes

Assess Maturity

Where we are now

Design Workshop

Define Policy

Where we want to be

Whilst there are different ways to go through this, in the author’s experience an EMS Workshop has proved to be the most efﬁcient way to mobilise the process.

Core Operation – The Energy Management System

5.1.1 The EMS Design Workshop

The EMS Design Workshop deﬁnes the aims and outcomes of the EMS. Its outcome will be the basis of design for the system. It is essentially a Team-oriented organisation and process design process. Different companies and locations may have their own structured problem solving techniques which are used in such situations in which case they should certainly be used.

5.1.1.1 Timing and organisation

Typically a 1 to 2 day workshop would be sufﬁcient, ideally held at an off-site location. It is best that the Energy Maturity Survey (section 4.2) has been carried out ﬁrst and the results circulated to attendees. In preparation the attendees should think about how their current position and how energy consumption is affected by the job/discipline they work in. A clear set of aims and outcomes for the workshop needs to be developed in advance.

5.1.1.2 Attendees

The aim is to get a cross-section of people who represent areas of the company which inﬂuence how energy is consumed by the operation. A key outcome will be arriving at a consensus as to how energy is managed and how this could be improved so full representation is important.

Suggested attendees (for a ﬁctitious typical manufacturing site)

• Site Management Team member with nominated Energy Responsibilities

• Energy Manager/Coordinator

• Operations Manager

• Process Engineer

• Operations representative(s)

• Maintenance Engineering representative(s)

• Planning/Scheduling

• Utilities Manager/Engineer

• Corporate Energy Focal

• Training Coordinator

• Finance/auditing/QA/data management

• External facilitator

• Other specialist engineers/roles as appropriate to the facilities

5.1.1.3 Agenda

Suggested items for the workshop agenda could include the following. These are suggested as topics for debate which may be for the whole team or break-out/syndicate groups. Not all will apply and there may be others however the main strand is arriving at a consensus as to the current energy operation and for the workshop to have articulated the issues that need addressing (perhaps including suggested solutions) in the design of the EMS.

• Review of current energy performance

• The Case for Change

• How does the Site/Company manage energy now?

• Map out current energy planning and performance review ﬂow chart

• Current blocks to good energy efﬁciency practice

• Future energy environment and constraints affecting it

• Describe good practice in 5 years time: operations, technology, maintenance, people, etc

• Identify new work practices and responsibilities

Core Operation – The Energy Management System

• How does the site energy operation ﬁt into the bigger corporate model?

• Energy measurement and information structures

• ISO 50001 familiarisation and requirements

• Competencies and training issues

• How to address wider engagement with the Site Community on Energy Issues

• Take-away actions

5.1.1.4 Outcomes

The style and operation of the workshop will depend on local company culture and practices. However the

basic aim is to come away with a clear understanding of the current energy operation and the issues that need to be addressed to meet future business and corporate environments and constraints. This

will then feed the design of the individual EMS components. This design work may be done by a dedicated team or (partly) by subgroups with take-away actions from the workshop.

5.1.2 Basic Components of EMS – ‘Essential Best Practice’

A comprehensive system following ISO 50001 can be developed and reference is made to sections 5.2 and Appendix A should the user wish to go down this road. Otherwise the following areas comprise the core elements of ‘Essential Best Practice’ which any organisation wishing to establish effective energy management activities should address.

5.1.2.1 Policy and Strategy

The Energy Policy provides the framework and environment to everything that follows. It is the mirror that should be used for testing energy activities and plans. There may be a Corporate Energy Policy that should be followed. It may need developing from scratch.

Policy Issues to be considered include:

• Long term energy targets

• Industry positioning (e.g. top quartile performer)

• Capital Investment Policy for energy

• Inviolable Constraints to operation (e.g. a no-ﬂaring policy)

• Business Policies – (e.g. to be robust from effects of local power supply irregularities)

• Staff competency and communication standards

• Working Practice standards – safe operation – legal requirements

• Wider Community targets and aspirations

Once the Policy is established it invariably leads to the strategy document and the subsequent action plans. The strategy articulates the steps needed to achieve the Policy and the subsequent action plan is the detailed realisation of this.

In developing a site energy strategy it is vital that all relevant parts of the organisation are addressed. We have seen that there are many inﬂuences on energy consumption and hence to ensure sustainability that must be reﬂected in the strategy. It is recommended that each major activity should be reﬂected in this to ensure cross-site recognition of the energy drivers. Typical of the issues that could be addressed are:

Core Operation – The Energy Management System

Site:

• Overall site energy targets and development of site roles and responsibilities for energy

• Key links to Corporate Energy Strategy

• Major energy project delivery goals

• Community issues

• Financial provisions for energy

• Procurement standards

• Registration to ISO 50001

Operations:

• Development of target setting and performance review processes (EMIS)

• Key operational changes (e.g. removal of high sulphur fuel)

• Development of operational energy roles and accountabilities

• Targets for energy-related operational procedures – (e.g. sootblowing frequency/operator rounds)

• Use of energy check lists

Maintenance:

• How do maintenance and availability activities affect energy consumption?

• Planning of contracts for servicing and cleaning

• Development of register and strategy for Energy Critical Equipment

• Steam leaks, traps and lagging

• Equipment condition and performance monitoring strategies

Technology:

• Energy Efﬁcient Design standards

• New Technology and R&D exploitation strategies

• Technical auditing and Benchmarking

• Plant Improvement programmes

• Awareness and gatekeeping of external developments. External initiatives/collaborative funding opportunities

Capital Investment:

• 5 year Capital Plan

• Development of capital planning metrics and hurdle criteria for energy projects

• Funding options

• Joint ventures

Culture and Communications:

• Energy targets in staff appraisal, communications, competency gap analysis

• Training and development courses (general and speciﬁc)

The foregoing is neither exhaustive nor mandatory – it is based on a few real-world cases – but gives a ﬂavour for the sort of issues across the board that will need to be assembled into the Site and Departmental Energy Strategies. In each case the strategy should then be worked up into a (resourced) action plan aimed at delivering the strategic items over a given time frame. Again, documents like the Carbon Trust Best Practice Guide contain useful sections on Strategy Development.

Core Operation – The Energy Management System

5.1.2.2 Accountabilities

The Carbon Trust evaluation matrix (section 4.2) and the preceding discussion have highlighted a long standing issue concerning energy accountabilities. The cross-site inﬂuences on Energy mean that there has to be accountability for Energy issues at the highest level (Site Management Team). Only in this way can the correct span of control be achieved. Similarly, production managers, area managers and other staff with speciﬁc energy-related responsibilities need to be held accountable for the energy components of their jobs. These need describing in the documented Energy Management System.

5.1.2.3 Organisation

Many organisations do have an Energy Manager or focal point. That is a good start. This has been observed in a variety of positions and backgrounds: the position may have been part of Operations, Process Engineering or sometimes as part of the book-keeping/Internal Audit team. Incumbents have been Engineers or sometimes Finance analysts. It has been both a part-time and full-time position. Sadly, in too many cases, it has been observed as a low-ranking position without the inﬂuence and authority to address the issues raised so far. It is not simply a performance-metric position or benchmarking position. The Energy Manager has to be a catalyst for change with the mandate and spheres of inﬂuence to tackle the cross-discipline issues that affect energy efﬁciency. It should be ideally a signiﬁcant position within the Process Engineering management structure.

In developing this position the Carbon Trust Matrix can help deﬁne roles and responsibilities for this position. Section 11.1.1 discusses the job competencies for Energy Manager in more detail.

It does not stop there. Operational Energy Focal Points with key ownership of the Departmental Energy Plan should be established within the various Operational Areas. A successful solution at one location in the author’s experience was establishing one particular Operational Shift as ‘the Energy Shift’. The Shift had speciﬁc energy-related responsibilities and developed ownership and skills in this ﬁeld, in particular making use of the quieter night shift to pursue their tasks (other shifts had similar focuses – reliability, environment, etc.).

Fundamentally the development of an Energy Management System requires the Company to develop and address the organisational responsibilities for energy. This is a basic need.

5.1.2.4 Competencies

The EMS shall require the site to assess its competency needs to support the programme and institute the relevant training to achieve those requirements. This will encompass several levels of expertise from specialist engineering skills to general staff appreciation. Local circumstances will dictate how certain skill or competency requirements are met – through in-house staff or calling on specialised energy skills from external or Corporate providers.

Using the organisation previously deﬁned there are many competency analysis and mapping tools commercially available which can be used for monitoring employee skill databases. It is highly likely that systems may already be in use as part of the Company HR/staff appraisal system in which case adding in Energy-related competencies should be a relatively simple task.

Core Operation – The Energy Management System

Skills and Training Check list:

• Energy Strategy and Business

• CO

and Emissions trading

• Utilities Engineering

• General Energy Efﬁciency techniques for Process Engineers

• Operator Good Practice techniques

• Specialised Operator Training – e.g. furnace operation

• Specialised Technical Training – e.g. Pinch Analysis and fouling abatement

Energy competencies and training will be looked at in more detail in Chapter 11.

5.1.2.5 Work Processes

With a strategy, organisation and deﬁned competencies in place the ﬁnal key element of the basic EMS are the deﬁned energy-related work processes. These do not need to be complex. The aim is to deﬁne and capture the important stages of those key activities without which the Energy Policy would be at risk. They also form the basis for the Improvement Loop – i.e. the documented process which can be improved and updated by a means of audit and experience so as to improve the operation.

The formats can and should be simple – perhaps just a ﬂowchart. Clarity and simplicity are key in providing an understandable process that can be easily followed and executed. As always an important process is the audit/check process to ensure compliance.

Suggested processes that may be suitable in a typical chemical process site include:

• Target Setting and Performance Review

• Energy Efﬁcient Maintenance procedures

• Energy Reporting

• Operational Procedures

• Energy aspects of Design and Plant Change

• Auditing Energy Performance

• Financial and accounting processes for energy (procurement/contracts)

• Handling Energy within Planning and Scheduling

• Key energy calculations and correlations (e.g. fuel gas caloriﬁc value, meter compensations)

• Auditing the Management System compliance

This list is neither proscriptive nor exhaustive. The ﬁrst two topics will be examined in more detail in Chapter 7.

5.2 ISO 50001

The forgoing describes the basic development of an Energy Management System. These should fulﬁl the important requisites of this topic; given the right commitment and organisational discipline a company/site will be able to reap the major beneﬁts of working this way.

However, especially if the company or site already has a strong culture of systematic process management (e.g. registrations to ISO 9001 and ISO 14001) then the development and formal registration to the new Energy Management standard is a logical step and of course provides the discipline of external audit and system review which can play a major role in ensuring long term sustainability of the management processes.

Core Operation – The Energy Management System

Following the development around the world of various local Energy Management Standards (EN16001:2009 in Europe and ANSI MSE 200:2005 in the USA), ISO 50001 was released by ISO in June 2011 and is suitable for any organisation – whatever its size, sector or geographical location. The system is modelled after the ISO 9001 Quality Management and ISO 14001 Environmental Management Standards and like those, ISO 50001 focuses on a continual improvement process to achieve the objectives related to the environmental performance of an organisation. The process follows the same Plan-Do-Check-Act approach (Plan-Do-Check-Act, PDCA).

However, a signiﬁcant new feature in ISO 50001 is the requirement to “...improve the EMS and the resulting energy performance” (clause 4.2.1 c). The other standards (ISO 9001 and ISO 14001) both require improvement to the effectiveness of the Management System but not to quality of the product/service (ISO 9001) or Environmental performance (ISO 14001). Of course it is anticipated that by implementing ISO 9001 and 14001 that an organisation would, in fact, improve quality and environmental performance, but the Standards do not specify it as a requirement.

ISO 50001, therefore, has made a major leap forward in ‘raising the bar’ by requiring an organisation to demonstrate that they have improved their energy performance. There are no quantitative targets speciﬁed – an organisation chooses its own then creates an action plan to reach the targets. With this structured approach, an organisation is more likely to see some tangible ﬁnancial beneﬁts.

Core Operation – The Energy Management System

5.2.1 Plan-Do-Check-Act

Responsibility of Top Management

Energy Policy

Management Representative

Energy Review

Objectives and

Action Plans

Implementation and Realisation

Communication

Training

Awareness

Operational

Control

PLAN

ACT

Monitoring

CHECK

Management Review

New Strategic Goals

Optimisation

Analysis

Corrective Action

Preventive Action

Internal Audit

The 4 phases of the PDCA circle are:

PLAN: The overall responsibility for the installed energy management system must be located with the top

management. An energy ofﬁcer and an energy team should be appointed. Furthermore the organisation has to formulate the energy policy in form of a written statement which contains the intent and direction of energy policy. Energy policy must be communicated within the organisation. The energy team is the connection between management and employees. In this phase the organisation has to identify the signiﬁcant energy uses and prioritise the opportunities for energy performance improvement.

DO: The stated objectives and processes are now introduced and implemented. Resources are made available and responsibilities determined. Make sure that employees and other participants are aware of and capable of carrying out their energy management responsibilities. The realisation the energy management system starts.

CHECK: An energy management system requires a process for compliance and valuation of energy-related regulations. Internal audit can help to verify that the energy management system is functioning properly and generating the planned results. The processes are monitored with regard to legal and other requirements (customer requirements, internal policies) as well as to the objectives of the energy management of the organisation. The results are documented and reported to top management.

ACT: The top management prepares a written valuation based on the internal audit. This document is called the management review. The results will be evaluated on their performance level. If necessary, corrective or preventive actions can be initiated. Energy-relevant processes are optimised and new strategic goals are derived.

Core Operation – The Energy Management System

5.2.2 Beneﬁts of Certiﬁcation

Certiﬁcation proves that the energy management system meets the requirements of ISO 50001. This gives customers, stakeholders, employees and management more conﬁdence that the organisation is saving energy. It also helps to ensure that the energy management system is working throughout the organisation.

Another advantage of certiﬁcation is its emphasis on continual improvement. The organisation will continue to get better at managing its energy. Additional cost savings can be generated over several years. Furthermore certifying an organisation shows your public commitment to energy management.

5.3 Links to Corporate Systems

The picture painted so far has described an Energy Management System for a single manufacturing site. This may be part of a bigger corporate strategy contributing to an overall Company policy and energy performance targets. In which case, some of the processes, roles and information requirements may be given as part of the corporate system.

Planning &

Scheduling

Maintenance

Mgt System

Utilities

Optimisation

EMIS Data Base

Modelling and

Simulation

CO2 Reporting

Non

Conformance

Corporate

Benchmarking

& Reporting

For instance there may be requirements for standard periodic energy performance data returns and also the implementation of standard tools and packages. There may be speciﬁc roles and accountabilities. A lot will depend on the company culture and the degree of autonomy that individual sites have.

5.4 Development Support and further Information

Further information on ISO 50001 including development and registration is provided in Appendix A.

Energy Management Information Systems

6 Energy Management Information Systems

The Energy Management Information System (EMIS) is an essential component in managing energy on a manufacturing site. In format it may consist of a few simple spreadsheet reports through to a fullblown sophisticated graphics-based system with on-line models and reconciled energy balances. That choice is dictated by local circumstances, the important point is that pertinent plant and site-wide energy performance data are presented on a regular basis to those individuals who inﬂuence energy efﬁciency and enables them to make timely improvements.

To quote the well known adage; “If you can’t measure then you can’t improve.”

In the drive to improved Energy Efﬁciency an EMIS is the single most important tool at a site’s disposal. Whether it be investigating yesterday’s performance, ﬂagging an upcoming issue or deep analysis of historical datasets as part of a fundamental (capital) improvement initiative the concept of reliable and consistent energy data is the same. Given the disparate and cross-site nature of energy issues the EMIS is the place that draws the energy performance together into a consistent and digestible form.

Features of an EMIS include the storage of data in a usable format, the calculation of effective targets for energy use, and comparison of actual consumption with these targets. Elements include sensors, energy meters, hardware and software (these may already exist as process and business performance monitoring systems). Essential support includes management commitment, the allocation of responsibility, procedures, training, resources and regular audits.

6.1 Objectives

There are a wide variety of users of energy performance data operating with different purposes, responsibilities and on different timescales. There are often many different correlations and methodologies that can affect energy calculations (e.g. fuel gas caloriﬁc value correlations, key performance indicator methods).

Energy Management Information Systems

The objective of the EMIS is to provide a standard data reporting structure as the basis for analysis and decision making by the Energy Management System Users. It should encompass:

• A single cross-site database

• Common agreed calculations, models and correlations

• Flexible user-oriented reporting

• Agreed KPI hierarchy

• Easy access to historical records

This means that whether the user is a maintenance engineer investigating historical equipment fouling, an operator maintaining an efﬁcient operating point or a site manager looking at annual business performance, all users are working from a consistent set of data. It becomes the common site energy language. Generic deliverables are as follows:

• Early detection of poor performance

• Support for decision making

• Effective performance reporting

• Auditing of historical operations

• Identiﬁcation and justiﬁcation of energy projects

• Evidence of success

• Support for energy budgeting and management accounting

• Energy data to other systems

How these will be realised will depend on the local circumstances. The following sections should provide the background for the reader to specify the EMIS requirements for the particular site. A checklist on EMIS structure and functionality is provided in Appendix C.

6.2 The Components of EMIS

6.2.1 System conﬁguration – hardware/software

Typically the core of the EMIS will these days be a commercial process historian which scans process data from the instrumentation system (DCS, SCADA) on a regular basis. This may be an integrated part of the DCS structure. For most process unit energy variables (compressed) two-minute data are sufﬁcient. The database may be a virtual structure – i.e. a slice across several existing databases. However it is important that it is effectively site-wide thus enabling site-wide energy balances, KPIs and reports to be easily assembled.

For multi-location and/or remote operations web-based/cloud solutions may be appropriate.

Interface to other manufacturing support systems including relational databases such as maintenance management systems like SAP, accounting and corporate performance reporting may be considered.

Over the last 10 –15 years Windows-based systems have become the norm allowing easy interface between the core energy data and the huge variety of modelling, reporting and analysis tools that now all use Windows as their base operating systems. The requirements for the respective site management levels enables reporting and analysis to be very individual and customised; thus the Windows approach with intuitive interfaces is ideal.

Energy Management Information Systems

Reporting Options. Again, open to preference, be it ‘ﬁt for purpose’ reports using Windows’ standard tools such as Microsoft Excel or a sophisticated solution using any of the more complex graphics reporting packages that are now available.

6.2.2 Data Structures/KPI and Target Setting Philosophy

EMIS is fundamentally a cascaded target setting and reporting structure for energy data and operating variables. EMIS starts from high-level performance measures within the Site Manager’s portfolio cascading down through operational areas and structures to short-term control parameters at the plant operator level (e.g. Boiler/Furnace/Gas Turbine ﬁring conditions). At all levels performance measures (Key Performance Indicators – KPIs) frequency of review and appropriate corrective action loops need to be deﬁned (the EMS processes). Supporting this, tools, based on the analysis of (real-time) plant data, are needed to present timely and appropriate information.

Generally, an EMIS will look to group units within a site by their commonalities, e.g. a common utility supply, common operating objectives, common operation management for line responsibility, etc. Typically an energy balance is made around these units and KPIs are established and calculated on-line. KPIs could include: Energy Index at a site, Area or Unit level, total stack energy loss, Energy/feed ratio etc.

Target

Update

Period

Annual with

Monthly Revisit

Monthly with

Weekly Revisit

By Operating

Mode

Support

Tools

LP Models,

Business Plans

Energy Tools, Flowsheeters

Site

Area

Management

Unit

Management

Equipment

Operation

Target

Site Energy

Index

Aggregated Unit

Data + Common

Utilities

Plant Energy

Index

Equipment

Speciﬁc Energy

or Loss

Review

Period

Monthly Daily or Monthly

Monthly Monthly Monthly Monthly

Daily Real Time

Real Time Real Time

Calculation

Frequency

Energy Measurements Flows, Temperatures,

Pressures

Daily Operating Targets

for Energy Drivers

The Site picture is built by aggregating the energy balances and KPIs from individual units, though operational areas to the overall Site picture. It is important that this common approach is adopted since it will ultimately enable a consistent drill down of data: the energy picture ‘adds up’. Similarly it is important that a consistent set of correlations, engineering calculation assumptions and economic values are used across the board – a standardised modelling philosophy is adopted.

The format of the KPIs that are adopted will be very much driven by the Industry and local circumstances. Some industries have common (international) approaches (e.g. the EII, Energy Intensity Index, developed by Solomon Associates which is the de-facto standard in the Oil Industry). Typically they will be of some form of feedrate-adjusted energy consumption ﬁgure or ratio. Particularly at the site reporting level then consistency with or adoption of standard benchmarking calculations is a very good idea.

Energy Management Information Systems

Other KPIs may be site or plant speciﬁc, perhaps reﬂecting a key energy related issue (e.g. “percentage imported fuel gas”) and there should be provision, if possible, for economic ‘Price of non-conformance’ data. This should be readily calculated from the performance gaps from energy targets and the associated fuel costs. Having such data for each target and aggregating into unit and site reports also allows quick drill-down analysis to identify bad actors and root causes. Modern dashboard-type displays and reports can easily exploit such data to good effect.

The organisational processes of target setting and review will be covered on in Chapter 7. An important consideration is the timely update of KPIs and targets when new production planning data becomes available as the year progresses. In particular the shift from annual headline targets to monthly operation targets reﬂecting actual production plans can be signiﬁcant; different feedstocks and changes in production modes all affect energy consumption and should ideally be quantiﬁed in the target setting process. The accompanying ﬁgure illustrates how an annual Business Plan target needs adjustment for the actual Plan, seasonal averaging effects and maintenance activities to arrive at a monthly energy target pertinent to the month ahead. The actual achieved production schedule (actual vs. plan) also accounts for part of the variation before the true operational energy inefﬁciency gap is shown, which then forms the basis for investigation and improvement.

100

Energy/feed

Annual Business

Plan

Planning Variation Seasonal Variance Maintenance Target Monthly

Production Planning Effects on Energy Targets

Plan

Gap to Production

Plan

Operations Efficiency

Gap

Actual

The foregoing highlights a major issue in developing Energy KPIs and Targets. Effects such as these can severely test the validity (and hence user acceptance) of targets. Similarly, variations between production modes may need attention in target setting. This has the potential to lead to a proliferation of advanced target-setting systems involving combinations of ﬁrst principles and statistical modelling to account for the aforementioned variations. It can be done and it has been done. However caution is advised. The balance between modelling complexity, support levels and end beneﬁt is a ﬁne one. It may be better to have simple target setting structures across a site with the use of more complex techniques limited to speciﬁc high-beneﬁt areas. Sensible and ‘aware’ performance interpretation is important.

Energy Management Information Systems

6.2.3 Energy Driver Variables

(Sometimes called Energy Inﬂuencing Variables)

Whilst the KPIs are the visible calculated manifestation of energy performance, the energy drivers are the process variables which are the main inﬂuences behind the changes and variability in the selected energy KPIs. Hence they form the focus of attention in our attempts to optimise the KPIs against their target values.

KPIs can be classiﬁed broadly into two categories: non-actionable parameters and actionable variables which can be manipulated. Non-actionable are those inﬂuential variables that are beyond operator control. Examples include ambient temperature, feedstock quality or product price. They impact on the energy consumption but are not something that can be changed or corrected operationally. Actionable variables, on the other hand, are variables that operators can change to affect the operation. Examples are reﬂux ratios, reboil rates, recycle loops ﬂow and furnace air-fuel ratio. We use the term ‘driver’ for any causal and controllable variable that directly or indirectly inﬂuences the planned energy consumption (and hence this will inﬂuence the KPIs).

Analytical tools (e.g. statistical data-mining) and/or process engineering experience are used to determine the controllable and most inﬂuential drivers to manage the energy loss. These drivers will be reviewed for constraints like product speciﬁcations, safety and operational envelope of equipment. Targets will then be established for optimal energy use with due consideration to other hierarchical inﬂuences such as production demands, product speciﬁcations etc.

If it is considered appropriate, models (process,

statistical or hybrid grey-box techniques which

combine ﬁrst principles and statistics) can be established linking the driver variables and the KPIs, perhaps including a cost penalty function. This will allow a more detailed analysis of the contributing cost of non-conformance on the KPIs

Model

KPI

KPI = F(F

∆KPI = F’(∆T)

(MW, $$, tonnes)

1,F2

,T,Q)

and can be helpful in providing a drill-down and bad-actor structure.

Driver Variables

Although it is clearly not possible to set operational targets for non-actionable variables it is still important to understand (and be able to model) their effects on energy consumption as these will play an important part in the performance analysis (and maybe in target setting if taken to a more sophisticated level).

6.2.4 Use of Energy Loss Points

Probably the most widespread KPI in use by industry is some form of speciﬁc energy consumption – e.g. energy/feed. This is well understood, logical to calculate and accounts for one of the major impacts on energy consumption – throughput.

However there can be problems with this – for instance when the energy-to-feed ratio is non-linear. In particular when looking at unit and equipment performance then the idea of establishing targets for energy loss can be considered. Obviously the aim will be to minimise energy loss.

Energy Management Information Systems

Consider a simple distillation column. Energy is

Qohead

input by feed preheat and reboil. Energy leaves the column as sensible heat in the product streams and the heat removed by the overhead condenser. Typically this is lost to low-grade non-recoverable energy sinks (atmosphere, cooling water etc). The operating conditions of the column (temperature, pressure, reﬂux etc) determine this energy value. Hence these are the drivers which inﬂuence the loss-KPI.

Qfeed

Qprod1

For a furnace the lost energy is the energy lost to atmosphere from the stack as opposed to that transferred as sensible heat to the product in the

Qpreheat

Qreboil

furnace tubes.

The concept of energy loss being the performance measure or KPI is the calculated

Qprod2

energy loss from the unit, i.e. it is a direct measurement of energy wastage. A target can be set for the normal acceptable loss value and models can be built for the relationships between the loss and operating conditions. Similarly price of non-conformance calculations can be included.

Whilst loss points can be more complex to calculate and visualise in comparison with a simple energy consumption they do focus on the wasted energy – energy consumption of course is the sum of wasted and useful energy.

6.3 Operating with EMIS & User Interfaces

The EMIS is effectively the energy hub for a manufacturing site and as such will have a variety of users and purposes. These will vary from ﬁxed formal multi-user reports to one-off customised and ad-hoc applications.

• Annual and monthly performance reports to Management

• Real-time energy driver monitoring in the control room

• Specialist technical engineering applications, often integrated with modelling/optimisation tools

• Ad hoc data analysis and troubleshooting

• Data interfaces to other IT systems

Fortunately modern client-server and peer-to-peer Process Historians typically using a Windows interface are well suited to the variety of uses outlined.

It is important that a system manager and/or application guardian is appointed. The more formal reports need correctly managing and are best developed using a reporting package which allows controls and consistency. Similarly the integration of operational target setting with existing plant instruction processes and the DCS database also needs very careful consideration.

Energy Management Information Systems

In recent years application integration for tools and software running on Windows has become very easy. Transfer of archived process data into a modelling or optimisation package for instance is now an easy exercise. And that ﬁts in well with the concept of the EMIS as the energy hub. However there is a ﬁne line between the use of software tools and development of correlations and models for one-off/single user investigations and a sustainable situation where similar tools and calculations form the basis for repeatable longer term use. The well-known phenomenon of ‘skunk’ spreadsheets – complex, undocumented and hence impossible to pass onto a new user – illustrates the problem.

Companies are starting to tackle these issues and may have standards and procedures in place. The EMIS Guardian plays a key role in managing this process – there is a delicate balance between encouraging and facilitating energy data exploitation and sustainable long term applications.

6.3.1 User Interfaces

Many options are available in developing User reports and interfaces with varying degrees of dynamic reports and displays. Modern screen building tools can be very powerful. Local standards and norms will play a part. The following guidelines are presented to assist in the design process.

• A clear vision is needed of who the Report User will be

• Only display Information that is relevant to, and can be impacted by, the user

• EMIS displays should be functionally consistent. This means that the intended functionality of each display must be clear and once the analysis is done on that display, it should give pointers to the next display to be accessed in order to complete the energy analysis

• Consider using drill-down techniques driven by energy indices or ﬁnancial cost calculations to navigate multilayer nested reports from high level indices to individual items of energy equipment. Dials or plus/minus bar charts can be useful in displaying the bad actors and linking up to the next level screen

• Multiple displays can be very useful for exception and pattern recognition. e.g. multiple trend displays for multiple (similar) furnaces

• Consider including causal information, for instance:

- (Online) calculations showing energy impact of off-target drivers

- On-line adjusted KPIs (e.g. effect of external conditions on performance, load dependent targets)

- Rule-based logic providing operator advice

• Quick links to trend information are very useful

Many examples can be found – a small selection is provided to give guidance or inspiration to the designer. All have been built using real-time and historical plant data in PC-based user-display packages.

(The examples have been taken from sales literatures, conference presentations, etc.)

Plant overview with major energy classes:

Historical KPI reporting plus dashboard:

Energy Management Information Systems

Part of drill-down structure at energy driver level showing target, actual and effect upon

energy consumption:

X-Y plot indicating actual performance against load/efﬁciency model:

Boiler 2 Efficiency

Actual

Efficiency, %

Model

Net Heat Output, MW

Energy Management Information Systems

Tabular/bar chart approach showing energy drivers and their contribution to

gas turbine efﬁciency:

Actual Expected Deviation MW

MECHANICAL DEGRADATION Generator Output MW 25.231 26.544 -1.313

OPERATING PARAMETERS Inlet Temperature deg C 485.1 520.0 -1.405

-1-2-3 +1 +2

Extraction Pressure kPa 480.2 500.0 +0.108 Exhaust Pressure kPa 9.5 8.0 -0.878

TOTAL DEVIATION -3.488

Dynamic Overview display:

Size of panel indicates relative energy consumption of each area – colour indicates deviation from target. The display drills down to more detail using the panels.

Energy Management Information Systems

6.4 Development of an EMIS

There follows a general set of guidelines for developing an EMIS. The scope may vary from simple ﬁt-forpurpose reports through to a major modelling and graphics package so the ﬁnal plan will need adjusting. The programme follows a typical project execution plan and should ideally be incorporated into an overall Energy Management System roll-out.

Feasibility

Study

EMIS

Definition

Driver & Target

Development

Core Activities

A short Feasibility Study is used to determine the main issues, opportunities and blocks to an EMIS and whether it is a feasible proposition for the site. Typically a one week on-site activity, the purpose of the Feasibility Study is to make a preliminary assessment of the viability of the EMS implementation. Key issues, constraints and the availability of crucial prerequisites which could impact project success need to be identiﬁed together with the ﬁrst pass project economics to indicate project viability. The EMS Design Workshop (section 5.1.1) can generate much of the information and site philosophies needed.

The Deﬁnition Phase is essentially the design process. The aim is to produce a detailed design that fully deﬁnes the EMIS in terms of structure, technical architecture, scope, interface, management system , etc. and is unique to the Site in question. The site is split into EMIS areas, energy balances and KPIs are deﬁned. It will allow a ﬁnal (say) 10% project cost estimate to be prepared. Beyond this point the detailed work of coding, analysis and ﬁnal implementation can then take place. The speciﬁcs of project approvals, estimate levels will clearly depend on local procedures – the model presented is typical of a normal project development cycle. The Driver and Target Development phase handles the detailed design and coding of the EMIS prior to ﬁnal implementation and rollout. At the end of this phase all calculations will have been deﬁned and checked, drivers, constraints and KPIs fully identiﬁed, displays prepared – all in readiness for ﬁnal commissioning in the operational system. Completion of this phase marks the end of development work. The ﬁnal phase tackles the training, roll-out and implementation of the ﬁnished system and bringing it into operational use. This will clearly involve many parties and success at this point will inevitably determine the potential long term success of the project. It may be worth considering involving Change Management techniques to help design and support the process.

Implementation,

Hardware,

Tools &

Procedures

Sustain Phase

Activities

6.5 Core Activities - System Building

The rest of this section deals in more detail with a step-by-step approach to developing the EMIS.

6.5.1 Allocate Areas of Operation

Deﬁnition of EMIS System Boundaries or Areas of Operation. The deﬁnition of an EMIS Area is dependent on several factors - commonality of purpose, common operational management, common utility supply, etc. Typically, groups of units which are tied together by some related function into an Operational Area. Mapping out the site into a logical set of Areas is the ﬁrst step in any EMIS design. It is likely to be inﬂuenced primarily by organisational and departmental limits.

Energy Management Information Systems

For every EMIS Area of operation the following streams need to be identiﬁed

Allocate Areas of Operation

and their associated measurements (tag variables) listed. The aim is to identify all streams carrying energy across the Area Boundary, associated tags, ways to estimate or calculate missing meters and equations to determine their heat

Develop Energy Balance

content.

All crucial measurements together with type of meter, measurement range,

Compute Loss Points

design accuracy, known problems should be listed. Missing meters have to be identiﬁed.

Feedstocks

Identify KPIs

Identify Drivers

All feedstocks entering the EMIS Area should be included. The heat content of feedstocks (sensible and latent heat) is required for an EMIS energy balance. Hence suitable online measurements (e.g. temperatures) are needed if the

Identify Constraints

heat content of feedstock signiﬁcantly changes.

Meter requirements:

Set Targets

Appropriate ﬂow, temperature, pressure and quality measurements to determine mass ﬂow and heat content.

Compute £££ Opportunities

Products

Besides the feedstock the distribution of products also determines the required

Build Displays

process energy and the corresponding losses. All product ﬂows leaving the EMIS Area thus have to be included. Product ﬂows in this sense are ﬂows to storage tanks or to other units outside the operational area. As with feedstocks

Deploy EMIS

the products also carry a varying energy content that is relevant for an EMIS. Suitable online measurements are required if product conditions change.

Meter requirements:

Appropriate ﬂow, temperature, pressure and quality measurements to determine mass ﬂow and heat content.

Classes of Energy

All types of energy streams entering or leaving the system boundary that are inﬂuenced by plant operation are called Classes of Energy (CoE). It is possible that a CoE only virtually crosses the system boundary, as is the case, in general, with indigenous fuel and own power production. Typical CoE are:

• Steam at different pressure levels

• Tempered water

• Fuel (fuel gas, fuel oil, natural gas, coke, etc.

• Electricity

• Boiler Feedwater and Condensate

• Air (if signiﬁcant)

All these Class of Energy are required to build the energy balance of an area and unit.

Energy Management Information Systems

Meter requirements:

• Steam and tempered water:

Flow, temperature and pressure (ﬂow meter in steam lines preferably at superheated conditions to avoid condensation in pressure taps)

• Fuel gas:

Flow, (pressure, temperature and molecular weight might be required for density compensation), Low Heating Value (LHV) or composition or density to be used in an LHV correlation.

• Fuel oil:

Flow, LHV or alternatively density and sulphur content to be used in an LHV correlation.

• Electricity:

In general all net electric power import will dissipate into heat (apart from any hydraulic head gain for product streams leaving the EMIS Area at higher pressures than the feed ﬂows). Depending on the type of EMIS Area electricity might or might not be an important source of energy. Even when electricity is a signiﬁcant source sometimes only monthly integrator readings are available. In such cases a correlation between monthly Area or unit load and average monthly power consumption may help. For EMIS purposes this speciﬁc electricity consumption together with the online load can be used to substitute missing electricity meters.

Another important consideration is the fact that the units supplied by a power distribution network do not necessarily match with the units inside the EMIS Area. Further, in most applications, there are not many energy savings opportunities in electricity. Hence, reasonable estimates of electricity consumption will sufﬁce. However, in applications where signiﬁcant energy savings will result from reduced electricity consumption (e.g. use of variable speed drives), at least localised electricity consumption meters are required for accurate monitoring and sustenance of savings.

6.5.2 Energy balances

The aforementioned boundary and variable analysis will allow the construction of Energy Balances for each Area of operation. This is a key step in the design of an EMIS. We must ensure that all relevant energy ﬂows are identiﬁed and available at sufﬁcient accuracy. Trending the imbalance over a sufﬁcient period in time (e.g. 1 year) gives a good means to assess the accuracy.

The overall site energy balance should include the energy loss points identiﬁed below (cooling water, ambient air, etc.). While it is not essential to have perfect closure of energy balance, it is preferred to close the balance as accurately as practically possible. The accuracy of closure depends on availability and quality of measurements, quality of estimates of physical properties, and on completeness of variable identiﬁcation. If the lost energy cannot be quantiﬁed due to lack of measurements at least the sum of all loss points has to be calculated as the difference between useful energy in and out.

Energy Management Information Systems

6.5.3 Identiﬁcation of Energy Loss Points

By understanding where energy is lost on a unit and what process parameters drive that loss then we have a means to ensure that these losses are at a minimum. Alongside the Unit/Area energy balance it is necessary to identify the principal energy loss points in each Area. Typical loss points are:

• Furnace stacks

• Air coolers

• Water coolers

• Blowdown/venting In selecting the loss points a judgement has to be made between absolute size of a loss point, the feasibility or otherwise of impacting the loss, its relative size in terms of the unit energy balance and the total number of loss points. Typically we may consider loss points of >5% of the Unit energy balance to be of interest although this is not a hard ﬁgure. The key issue is that one should focus on controllable loss points – i.e. those which are affected by controllable drivers and also that show enough variation to be able to establish causal relationships.

Meter requirements:

• Furnace or boiler stack losses:

Stack oxygen and temperature plus ﬁred or absorbed duty, or ﬁred and absorbed duty.

• Air coolers:

Product ﬂow plus inlet and outlet temperatures.

• Water coolers:

Product or water ﬂow and corresponding inlet and outlet temperatures.

• Hot ﬂows to cold storage:

Appropriate ﬂow and temperature measurements.

It is important to make clear that the metering does not have to be direct (though it deﬁnitely is preferred that way). For example ﬂow rate may not be available on a stream being cooled. However, it may be possible to compute the ﬂow using mass balance either upstream or downstream of the loss point itself.

6.5.4 Preliminary list of KPIs

Based on the above-mentioned existing accounting methods, energy loss points ,etc. a list of typical energy related KPIs has to be developed. This list may include KPIs such as:

• Energy indices on a site, Area or Unit base

• Total throughput related losses in e.g. GJ/t, tonnes fuel/tonnes feed, etc.

• Loss point speciﬁc KPIs such as total loss at a speciﬁc water cooler, etc.

Refer to Section 6.2.2 for further discussion on KPI selection. Typically a 3-level KPI hierarchy (Site-Area-Unit)

would be appropriate.

6.5.5 Driver Development and Identiﬁcation

The drivers are the process variables which are the main driving forces behind the changes and variability in the selected energy KPIs. And hence they form the focus of attention in our attempts to optimise the KPIs against their target values. If we maintain the drivers at their targets then we are likely to be operating efﬁciently. Conversely, deviating from target allows us to understand why energy efﬁciency is not what it should be.

Energy Management Information Systems

There are many ways that drivers can be identiﬁed. In some cases good engineering judgement and plant experience will be sufﬁcient. In other cases statistical analysis can provide insight and understanding beyond the simple ‘rule of thumb’ into the detection of non-obvious drivers. Of course the results should be validated with experienced operating personnel. For these techniques to work there has to be sufﬁcient variability in the potential driver data set.

As there may be several drivers that inﬂuence a particular KPI, sufﬁcient effort should be spent to develop an understanding and model description of the correlations between them. While investigating constraints and targets for drivers, it is therefore important to bear in mind that not all drivers can be manipulated sufﬁciently – they may be tightly constrained or controlled, despite indication or even proof of lost opportunities to (further) improve the KPI(s).

Note that proper understanding of the underlying causality is crucial and therefore some form of causeeffect or what-if analysis needs to be performed. In case of insufﬁcient data or poor data quality, ﬂow sheet simulations can be considered. Again, the importance of operational involvement and buy-in at this step cannot be overemphasised.

6.5.6 Constraint identiﬁcation

Drivers can be manipulated to achieve the desired optimsation of KPIs. However, it is essential to ensure that any change in driver targets does not push the plant to an operating region in violation of other constraints. The process constraints that will be encountered include operating process limits, material of construction limitations, best practices, product quality considerations and safety limits. It is essential to ensure that all the constraints are identiﬁed and will not be violated while making recommendations for changes in drivers. There is a growth in companies who are implementing integrated alarm and process monitoring systems where a single reconciled database tracks variables across the alarm spectrum from operating windows through to hard safety-oriented trip alarms. Hence it is important that as part of the constraint identiﬁcation process limits and windows relating to drivers and associated variables that are identiﬁed in this database and are checked for consistency. Once established the constraints should be included in the database of KPIs and drivers to ensure that target advice does not infringe these limits. Where practical they can be included in driver and KPI reports to indicate the limits that a driver can be pushed to (e.g. minimum stack Oxygen content).

6.5.7 Setting Targets for KPIs and Drivers

There are several approaches to aid the setting of KPI and Driver Targets.

6.5.7.1 Historical Best performance

A quick and effective method to set targets for KPIs at each level of the organisational hierarchy is to identify a period of ‘best achievable’ performance from an energy perspective. The average KPI accomplished over this continuous time span would be a good target for the KPI.

In the event that a site has natural or other operational scenarios that result in markedly different energy performance, it is imperative to account for the same by setting different targets for different scenarios. As an example, the winter to summer variations or whether a reﬁnery is in diesel or gasoline mode will

Energy Management Information Systems

inﬂuence the energy performance of one or more units. A separate historical best performance should be determined for each scenario for the corresponding units.

Driver targets will generally come from the basic operational optimisation of the unit and need to be developed consistently with the other aims and constraints that determine day-to-day process operation. Thus ﬂow sheet tools, model-libraries, simulation techniques and operational experience are used to determine the basic level driver targets.

Further, long term or permanent operational changes that inﬂuence the energy performance should also be accounted for by resetting targets opportunely.

6.5.7.2 Statistical Correlation

Often it is possible to develop a correlation between the KPI of interest and the driver process variables that inﬂuence the KPI. This is an indirect approach that is often useful in the absence of a clear ﬁrst principles simulation model that describes the relationships between KPIs and drivers. Hence, a mathematical correlation between the KPIs and the drivers could be developed as follows:

KPI = f (Drivers)

Statistical and data-mining tools which can be used to develop these correlations are readily available. It is important, however, that the data sets used contain sufﬁcient variation (or ‘richness’) to allow sensible correlations to be established.

Once the correlation has been developed and validated, the same equation can be used to estimate KPI targets, using target values for the drivers in the equation. Thus consistency is established. Such modelling becomes particularly important if it is wished to evaluate the relative contributions of the actual driver performance to the energy performance gap. The driver targets are set bearing in mind considerations such as safety, margin, energy, etc.

6.5.7.3 First Principles Model

The most effective, but also the most expensive, method to determine KPI targets is to use a ﬁrst principles simulation model to determine both the driver and KPI targets. This step is generally not recommended for all KPIs, but should be resorted to in cases where any of the other options described previously is not tenable. Such models may already be held by the organisation for other uses.

The biggest advantage of this effort is the ability to have a uniﬁed look at several competing factors that come into play while setting KPI targets. As an example, often KPI targets are driven in competing directions by considerations of energy and margin. In such a scenario, the simulation model can be used to generate an optimal KPI target that maximises margin while minimising energy costs.

Energy Management Information Systems

6.5.8 Data Validation

Once the KPIs and sub-KPIs are fully identiﬁed then they should be conﬁgured in the real-time system and tracked for consistency and robustness over a period of time.

Instrumentation issues, such as missing meters and accuracy checks, should be resolved. A recommendation would be to check all meters pertaining to EMIS calculations prior to its development. Thereby, calculation of KPIs would have a sound basis. It is essential that at the end of this process robust calculations can run in real-time over a wide range of operating scenarios. In case of insufﬁcient data or poor data quality, ﬂow sheet simulations can be considered.

6.6 EMIS Skills and Competencies

EMIS development and implementation requires a full cross-section of skills. These will vary depending on the phase of the project. Fundamentally it is a change management project although there is a need for a strong operational and process engineering input plus some supporting skills in process IT. Clearly underpinning the technical skill areas is a strong element of communicational and project management skills.

A full examination of Energy Management skills and competencies is given in Chapter 11.

6.7 Key EMS Applications and Processes

To aid the development of the documented energy management system two key areas will be examined in more detail. Operating plant and maintaining equipment in an energy efﬁcient manner is fundamental to any efﬁciency programme – it is the basis of day-to-day operation. Many factors will inﬂuence the effectiveness and success of the activities. There are often potentially conﬂicting aims. Given this situation it is important that Energy considerations have an appropriate place in the decision-making.

Chapter 7 and 8 discuss energy management processes for Operational Performance Management and Maintenance Management respectively and suggest some generic methods that could form the basis for developing a sites local EMS practices.

Energy Target Setting and Performance Review

7 Energy Target Setting and Performance Review

Given the varied nature of the factors inﬂuencing energy, target setting and performance review process becomes the key activity in driving efﬁcient energy consumption. It is the opportunity to bring together the various energy-related strands into a single balanced process, at site, area or individual process unit level. In establishing such a concept the following important principles need to be adhered to.

• An integrated energy database is essential. Driven by process data and having easily accessed

historical data that can be assembled in user-focussed reports

• Consistent targets, KPIs, reports and review process need to be established across and appropriate

to different levels of the organisation

• KPIs and performance review should be appropriate to the span of managerial inﬂuence of the

review level

Set Daily Targets

Monthly and Weekly

Target Setting

Supply and

Planning Process

Monthly and Weekly

Performance Review

Performance Review and Corrective Action

Daily Operations Review

Operate Plant

to Targets

KPI and Target Setting

Production

Activities

Shift

Reports

KPIs and Reports

Make

Products

Plant

Operation

Two fundamental and complementary processes are developed: the Energy Target Setting Process which develops from high level annual targets through to real-time process variables under the control of the operator, and the Energy Performance Review Process which in a similar manner builds up from real-time corrective action through to Management Appraisal of Energy Performance.

Energy Target Setting and Performance Review

7.1 The Energy Target Setting Process

The core to performance monitoring is setting of appropriate performance targets. This process starts with high level annual site targets and develops, with increasing granularity and frequency, into daily operational targets for the energy-inﬂuencing drivers on the plant.

An important consideration is that the ﬁnal elements of the target setting structure at the operational level, are the operational parameters under the control of the operator, which inﬂuence and ultimately determine the energy consumption of the unit in question. So the whole philosophy is predicated on the need to establish optimum targets for these variables and monitor for operation away from target. These are the so-called ‘Energy Driver’ variables. They will be typically ﬂows temperatures, pressures, etc.

For example it is well known that the energy efﬁciency of a distillation column is improved as the column pressure is reduced. So a target for minimum column pressure is developed (consistent with product quality constraints) and the column monitored for operation at that pressure.

7.1.1 Site Energy Monitoring Targets and KPI Structure

Each site should maintain a dashboard of energy and emissions-related metrics. This will include both combined site-level KPIs and those pertaining to the principal units on Site.

A site owner of the metrics and the target-setting processes supporting them (e.g. agreed frequency for target setting/approval/sign off and up-dating) should be identiﬁed.

Targets for Key Performance Indicators (KPIs) should be determined as laid out in the following sections (annual/monthly/weekly targets setting) and performance against these KPIs reviewed as detailed in the subsequent section 7.1.2. Further details of Energy KPI structures for a site and the different metrics that can be employed are given in Chapter 6 covering Energy Management Information Systems. Typically it will encompass a yearly site Energy target (energy/feed) reaching down to unit energy and emissions targets (Unit Energy and/or Loss) for individual units calculated on a monthly basis.

Metrics calculated at higher frequencies (e.g. weekly/daily) will not be part of the site Dashboard although will be used as part of the overall performance monitoring process outlined in this manual. These metrics will need to be allocated targets consistent with the site Dashboard. This forms the cascaded target setting process which links high level annual targets for Site performance down to real-time plant variables directly under the operator’s control.

7.1.2 Annual Target Setting

Targets for site performance are agreed and signed off each year as part of the Annual Planning and Budget process. This includes high level Site Energy Targets, typically some form of energy intensity or speciﬁc energy target. This value of this target shall be determined in line with the feedstock and production premises upon which the Annual Plan is based together with knowledge of any planned factors that will affect energy performance: shut-downs, changes in equipment and conﬁguration, etc. Ideally a seasonal breakdown, for instance into quarterly planning targets, will provide a more realistic basis for the year ahead.

Energy Target Setting and Performance Review

7.1.3 Monthly Target Setting

Each month the Site should set targets for the Energy Dashboard for the forthcoming period. (Site KPIs and unit-level KPIs). These targets will be based on the Annual Targets updated with the latest 30 day Production Plan (feedstock slate, product pattern, plant expected availability). These unit level targets will then be used for assessing the Units’ performance during the coming month and act as the foundation for more detailed energy targets within the respective units.

Energy Constraints – the Production Plan should be checked against energy/emissions constraints (e.g. operation at CO

cap levels). In addition, based on the latest Production Plan, the Site KPIs and

month-by-month projection to year-end should be updated to reﬂect the latest production and availability picture for the full year.

7.1.4 Weekly Operational Targets and the setting of Operating Instructions

Based on the Production Schedule for the forthcoming week (produced by the Site Planning and Scheduling Department) a detailed set of energy targets for the sub-units and equipment in the particular Production Area should be prepared. This will allow the effect of scheduling decisions (yields, operating modes etc) to be reﬂected in realistic energy targets at a plant level. Typically these targets will be the operational driver variables such as ﬂows, temperatures, column reﬂux rates etc. These targets will then be ﬁnally validated and embedded as part of the Daily Operating Instructions.

(Refer to section 6.6.7 for target setting techniques).

Daily and weekly performance will be assessed on the basis of actual performance against these targets.

7.1.5 Daily and Real-time activities

Energy targets are included in the Unit Operating Instructions that are passed to the Operator. The Plant Operators are tasked with maintaining operation at the target values and noting causes for variance.

7.2 The Energy Performance Review Process

Energy performance should be reviewed in a structured manner, assessing energy consumption against metrics that are appropriate to the frequency, control and span of operations for the review process in question. Corrective and improvement actions shall be identiﬁed, documented and close-out should be tracked. Issues that require action beyond the control or scope of the particular review shall be passed on to the next higher-level review for resolution.

7.2.1 Daily Energy Performance Review

As part of the Daily Operations/Maintenance Meeting the energy performance of the previous 24 hour period in that Area shall be reviewed. The prime aim is to keep the plant running to targets.

Inputs will include:

• The overnight Shift Reports

• The Energy Management 24 hour performance report containing details of actual performance

against the energy targets for that period

Energy Target Setting and Performance Review

Identiﬁed actions will include:

• Suggested modiﬁcations to the Operating Instructions for the forthcoming period

• Short term maintenance and repair actions that need attention by day staff

• Issues that need escalating to a Site or Production Team level for further development

Where appropriate, issues should be logged into the Maintenance and/or non-conformance reporting systems (if used).

7.2.2 Weekly Energy Performance Review

Within a Production Area the 7-day unit Energy Performance will be reviewed in the weekly Production Team meeting (or monthly if that is the meeting frequency). The intent here is to identify issues and related corrective actions for the energy performance beyond the immediate previous 24 hours. In particular topics requiring more detailed investigation and follow-up.

Inputs will include:

• EMIS performance report for the previous period with actual performance against target

• Issues escalated from the Daily Area meeting

• Actions cascaded from the Monthly Site Energy Performance Review meeting

Ideally, the Site Energy Performance for the previous (7-day) period is reviewed at the Site-Wide Production meeting (if held) with a particular perspective on cross-site energy considerations (e.g. Utility and Fuel supply issues).

Inputs can include:

• Issues escalated from the various Daily Area meetings

• Weekly/month-to-date Site Energy Performance data

• Extraordinary energy issues arising from the forthcoming production plan. (e.g. special runs,

abnormal feedstocks)

Identiﬁed outputs could include:

• Common energy-related instruction to all units

• Suggested modiﬁcations to the Operating Instructions for the forthcoming period

• Speciﬁc instructions to a particular unit as a result of the Site debate

• Utilities constraints and implications on plants for the forthcoming period

7.2.3 Monthly Site Energy Performance Review

The overall Site Energy performance should be reviewed on a monthly basis at the Monthly Site Energy Performance Review meeting. This is an essential component in the management of energy on site and should be attended by the nominated Senior Manager with energy responsibilities and ideally also by the Site Manager. The metrics to be examined will include Site-wide energy calculations and the top level KPI for each unit based on the previous month’s performance. The meeting will review the previous month’s performance and also performance in the context of the yearly targets and year-to-date performance.

Energy Target Setting and Performance Review

Inputs will include:

• Monthly performance metrics (actual) for site and main units

• The Annual plan and updated targets (site and units)

Identiﬁed outputs will include:

• Identiﬁed longer term items (special studies) to be taken up through the Corporate business

improvement process, perhaps leading to eventual capital investment

• Energy Issues for consolidation at the monthly site non-conformance meeting. (Training, skills,

energy responsibilities, work processes)

• Improvement and corrective action issues to be cascaded (via the Production Unit Manager) to the

Area Production Team meetings

• Updated energy plans for the rest of the year

Whatever the Company incident and improvement procedures that are adopted the key point is that Energy Performance Monitoring should generate corrective and improvement actions. For many years such meetings became an ‘explain away the difference’ process when targets were not met rather than a true improvement process.

The Impact of Maintenance Practices on Energy Performance

8 The Impact of Maintenance Practices on

Energy Performance

The role that Equipment Maintenance plays in Energy Efﬁciency is often underestimated. Issues such as the optimal cleaning of heat exchangers to ensure best heat recovery and the servicing of key equipment such as steam turbines and furnace sootblowers through to the more mundane topics of steam leaks, steam traps and pipe lagging all play an important role in maintaining energy performance. There is evidence that maintenance contracts, often managed by departments not necessarily aligned to process optimisation, have suffered in recent ﬁxed-cost reduction exercises. Hence the need for clear Energy Strategies and work processes for Maintenance activities.

In developing a strategy and work processes for energy-related maintenance activities the concept of the Energy Critical Equipment Register is presented. This is analogous to the better known ideas of Safety Critical Equipment and Quality Critical Equipment. In other words equipment whose failure has a signiﬁcant impact on the plant’s energy efﬁciency is identiﬁed and appropriate maintenance measures are put in place to mitigate the risk of failure.

Modern Maintenance tools and software mean this is a straightforward task and should be part of the normal maintenance planning tools. Ideally there are 2 components:

1) Statistical Risk-Based inspection tools which determine proactively and cost-effectively the optimum maintenance/inspection/testing task plan or speciﬁc requirements of equipment in its operating context. The aim is typically to maximise Reliability, Integrity and Availability. Costs of failure, impact on energy performance and repair are combined with statistical availability and performance models to determine the most cost effective inspection/repair/servicing schedule. So this could be an optimised cleaning plan for a heat exchanger (balancing cleaning costs against performance improvement) or a preventive maintenance schedule for a key turbo-alternator set. A (sampled) steam trap inspection programme could be another application.

2) Maintenance Management Systems (e.g. SAP) which schedule and record the outcomes of maintenance testing, inspection and repair. This is the workhorse which drives the schedules, maintains the inspection records and is in common use these days.

The Impact of Maintenance Practices on Energy Performance

Energy Critical Equipment

These may be supplemented by on-line machine and equipment monitoring tools, typically running in association with the Plant Process Historian which measure and evaluate the current equipment performance. Combining these tools into an integrated process allows the development of an Energy Critical Equipment strategy. The operational process will be laid down as part of the Energy Management System.

Start

Select Units and prepare

Energy

Balances

Evaluate

Equipment

Evaluation Criteria:

• High Energy Consumers

• Causes high energy loss when running inefficiently, fouled or broken down (Primary Loss).

• Causes high energy loss elsewhere when running inefficiently, fouled or broken down (Secondary Loss).

• Have instrumentation that can cause high energy inefficiency when faulty/wrong setting/fouled.

• Have safeguarding systems that can cause high energy inefficiency when faulty/wrong setting/fouled.

ECE Register

Reliability Data

Maintenance Costs

Energy Costs

Reliability and

Inspection Tool

Maintenance Management

System

Execute

Maintenance

Activity

Control Measures:

• Testing

• Inspection

• Repair

Real-Time Asset

Monitoring

Tools

Performance Assessment

Optimisation

Making a Step-change: Opportunities, Auditing and Improvement Projects

9 Making a Step-change: Opportunities, Auditing

and Improvement Projects

The foregoing chapters have looked at building Energy Management Systems and the related information provision. These provide the foundation of culture, organisation, process and data upon which to build energy improvement projects. This chapter now considers the mechanisms for identifying speciﬁc energy improvement ideas and projects.

Inevitably there are several approaches possible and there is much scope for overlap in terms of timing and technical content. The adopted methods will inevitably reﬂect local conditions and priorities. The methods presented here have separate distinct aims but could be combined or rationalised as the user wishes. They may be carried out by local staff, corporate specialists or external consultants and suppliers as part of a more turnkey approach. Each way has its merits and downsides, in particular the balance between specialist and local knowledge.

Benchmarking

Walkthrough

Key Issues

Potential for Improvement

Strategy/way forward

Comprehensive Ideas Generation

Project Assessment

Maturity

Project Sheets

Execution Plan

Can We do Better?

Reacting to Change

What’s Happening outside?

New Opportunities

Energy Walkthrough – a short (i.e. 1 week) assessment of the overall energy performance and scope for energy savings on a manufacturing location. Delivers energy health check, key strategic issues, outline ideas and suggestions for improvement.

Opportunities Identiﬁcation and Project Assessment – typically a 1 to 2 month exercise with in-depth analysis, identifying energy efﬁciency opportunities and developing a prioritised project list which can then be used a basis for a detailed project roll-out.

Making a Step-change: Opportunities, Auditing and Improvement Projects

Generating Ongoing Improvements – A mature site may have started off with a dedicated improvement plan and an initial set of energy projects however it is to be hoped that once a certain maturity is reached then the EMS processes will continue to generate ideas for improving energy efﬁciency – that is a reﬂection of reaching a true energy improvement culture.

9.1 The Energy Walkthrough

Typically a 1-week exercise, the Energy Walkthrough aims to identify energy inefﬁciencies within the organisations process, storage and handling and utilities units. It is a gap analysis, reviewing facilities against best practices and recommending opportunities to improve energy efﬁciency within those facilities. The result is a picture of the highs and lows of a locations current energy performance, can help shape an improvement programme and set the scene for the development of the site’s energy strategy.

The walkthrough is an interactive interview process. Management, Process Engineers and Operators will be interviewed and asked to provide data.

The interviews are based around the analysis of process ﬂow schemes. The ﬂow schemes provide a structure to discussions on energy theme. Perhaps 2 or 3 hours discussion per unit. The ﬂow scheme reviews start at the beginning of the process and move through the ﬂow diagram to all end points. The aim of the interview is to identify all areas where energy enters, leaves or is exchanged within the process and question whether this is as efﬁcient as it can be.

The output of the interviews is used to identify opportunities to improve energy efﬁciency. Simple technical, economic and operability criteria are identiﬁed for use in screening & prioritising opportunities for improvement. At this stage a detailed set of worked-up project proposals is not the aim – the Assessment programme provides that – but the Walkthrough should indicate the strengths and weaknesses of the current operation and areas of concern that need addressing.

It is worthwhile to include an Energy Management maturity assessment (see Appendix B) as part of the programme. A particular aim of the Walkthrough is to evaluate the relative standing and maturity of a sites energy operation and lay the foundations for the longer term development of strategy and improvement activities.

A comprehensive walkthrough template and interview checklist included in Appendix D.

9.2 Energy Projects - Identiﬁcation and Assessment

Whereas the Walkthrough is very much about identifying gaps and potential the Energy Project Assessment is focussed on generating improvement ideas. It is a more comprehensive and rigorous process which will deliver a prioritised portfolio of individual energy efﬁciency projects, each complete with beneﬁts estimate and preliminary cost and feasibility assessments.

The process may take perhaps one to two months depending on the size of the location and will involve a much more detailed line-by-line discussion of the units compared to the walkthrough. The objective is generally to identify a list of Project Proposals suitable for ﬁnal development, authorisation and subsequent implementation. As such, it is essentially a project scoping process consisting of idea generation, validation and a project deﬁnition phases.

Making a Step-change: Opportunities, Auditing and Improvement Projects

During the initial idea generation phase, a list of many observations concerning the energy performance is documented. At this stage they are merely observations (e.g. ‘rundown temperature for stream X is 25 °C higher than design’) – cause and possible action are not considered. The observations are then validated, streamlined and used to generate a list of opportunities

Benchmarks

Observations

Ideas

Gap Analysis

Knowledge

Best Practice

Tools

Energy Observations

Generate Ideas –

Create Opportunities

New Ideas

Rejects

for improvement. These opportunities are then reviewed and validated, tested against constraints in order to generate

Validate

a prioritised portfolio of projects for implementation.

Conceivably from 250 observations some 75 opportunities will be generated

Selected Opportunities

which are validated to a short list of 40 and eventually a list of 15 – 20 realistic project proposals. These will have order of magnitude ﬁnancial beneﬁt and cost ﬁgures (say +/- 30%) and be scoped

Prioritise

at sufﬁcient detail to allow a process developer to work them up into ﬁnal fully scoped and estimated project deﬁnitions ready for Management approval.

9.2.1 Team and Preparation

Final Project Proposals

Clearly a much more involved process than the Walkthrough, the Project Assessment process may involve a team of 3 or 4 engineers on site for a couple of months with support from specialist engineers as necessary. Indeed it may be appropriate to bring in (say) a furnace or turbine specialist for a dedicated cross-site equipment review as part of the Assessment if this is deemed appropriate. Generally a Utilities specialist is a useful full-time team member. Apart from the usual pre-visit supply of P&IDs, process manuals and so forth, a key preparation or early phase item is agreeing the ﬁnancial and business thresholds, energy pricing, methodologies and constraints with the site. These shape the decision-making of the process and much time will be saved if these are agreed and understood by all parties at the commencement of the Assessment.

9.2.2 Assessment Process and Operational Reviews

A suggested step-by-step approach to the Assessment process and the development of initial energyrelated observations into ﬁnal project proposal sheets is given in Appendix E.

Making a Step-change: Opportunities, Auditing and Improvement Projects

9.2.3 Project Generation and Validation

There are many well-known methods for assessing the ﬁnancial value of projects (simple payback, Life Cycle Costing, Proﬁtability Index, etc. These are touched on in section 9.4. Most companies will have a standard project evaluation methodology and a set of criteria/investment thresholds which must be followed. It is essential that these are understood before the Assessment starts.

Whilst these calculations are a normal requirement of the ﬁnal ﬁnancial evaluation for the worked-up project proposals it is useful to have a preliminary project vetting method. The following matrix system is a useful screening tool which can be used to whittle down the opportunities into a collection of potential projects. Such techniques are quite common and there are variations possible on this basic system. The break points will depend on the business and should be agreed and calibrated with the site staff before the Assessment begins. More categories can be added and it is also possible to add weighting factors to the categories. Again, whatever is ﬁnally adopted needs upfront agreement.

RANKING INDEX

1 2 3 4

Net Beneﬁts

Ease of

Implementation

Capex

<£50k pa £50k – £500k pa >£500k pa >£1m pa

Very Difﬁcult

>£1m pa >£500k pa £50k-£500k pa <£50k pa

Requires

Shutdown

Requires

Project Work

Easy/Quick

Ranking Score = Net Beneﬁts x Ease of Implementation x Capex (max score 64)

‘Quick Wins’ = Ease of Implementation = 4

and (Beneﬁt x Capex) score >8.

Such validation techniques are very useful and provide a quick and auditable element in the design and decision process. They are not meant to replace a rigorous ﬁnancial project justiﬁcation but are simply a means of eliminating unfeasible ideas in a logical and consistent manner.

9.3 Ongoing Improvement – The Mature Operation

The scenario presented so far has focussed on developing some form of structured improvement programme, typically as part of a new initiative to address a site’s energy performance. This will generate ideas and projects.

However it is also important that once the initial project activity is over and a site is operating at a more mature level of energy efﬁciency there has to be a culture of supporting processes in place to ensure the continual refreshment of energy efﬁciency ideas. The issues around sustainable energy performance have been discussed; the nature of the energy drivers is such that operational changes can quickly change the issues affecting energy. Two or three consecutive and unrelated processing changes could move a site’s utility balance from, say, an MP steam surplus to a shortage, thus radically changing the site energy strategy. External fuel pricing considerations could do likewise. Thus the cycle of opportunity and project identiﬁcation needs to continue – ideally as part of the Performance Review (section 7.2). It is conceivable that changing operational priorities and economics could revitalise project ideas previously rejected. So the database of opportunities, including those not so far carried out, needs to be maintained.

Making a Step-change: Opportunities, Auditing and Improvement Projects

The performance review process will undoubtedly generate many items requiring a quick ﬁx or short term corrective action and repair. However the review and discussion must also keep an eye open for more structural issues requiring larger scale intervention, capital projects and so forth. Gatekeeping of external developments, new technologies and services that may be exploited in the quest for improved energy efﬁciency is an important part of this activity.

It is this attitude that is absolutely essential to a long term sustainable approach to energy efﬁciency. A one-off set of energy projects will inevitably become out of date, fall by the wayside and site energy performance will deteriorate.

9.4 Financial Planning and Project Economics

Project investment entails signiﬁcant capital and associated costs over the economic life of the project. It is usually possible to accomplish the same result with several routes and we need to be able to make economic investment decisions about the correct way to proceed with the project. There are many textbooks and guides providing comprehensive introductions to Project Economics however this brief section provides an introductory summary. In all cases support from local company economists should be sought in the selection of discount rates, investment thresholds, etc.

9.4.1 Standard Project Economics Techniques

The principle underlying all types of investment is the net return expected from the proposed investment. This net return must be evaluated and compared with the overall investment in the project. The economic technique used to compare various design alternatives by projecting (discounting or compounding) associated costs over the economic life of the project, is known as Life Cycle Analysis (LCA).

The EU Energy Efﬁciency Directive speciﬁcally encourages the use of LCA as part of its minimum

requirements for energy efﬁciency auditing (ref. EED Annex VI)

Payback Period and Return on Investment are two methods of analysis frequently used. They are not fully consistent with the life cycle cost (LCC) approach in that they do not take into account all relevant values over the entire life period and discount them to a common time basis. Despite their disadvantages, these methods can provide a ﬁrst level measure of proﬁtability that is, relatively speaking, quick, simple, and inexpensive to calculate. Therefore, they may be useful as initial screening devices for eliminating more obvious poor investments.

The four principal types of analysis that follow are fully consistent with the LCC approach: Total life cycle cost (present value method), Net Present Value (NPV), Proﬁtability Index or beneﬁt/cost ratio and Internal Rate of Return (IRR).

Simple Payback

Simple Payback determines the number of years for the invested capital to be offset by resulting beneﬁts:

Annual Beneﬁts – Annual Operating Costs

Simple Payback Period =

Gain from Investment – Cost of Investment

All other things being equal, the better investment is the one with the shorter payback period.

Making a Step-change: Opportunities, Auditing and Improvement Projects

Return on Investment (ROI)

ROI is a performance measure used to evaluate the efﬁciency of an investment or to compare the efﬁciency of a number of different investments. To calculate ROI, the beneﬁt of an investment is divided by the cost of the investment:

Gain from Investment – Cost of Investment

Cost of Investment

ROI =

ROI analysis compares the magnitude and timing of investment gains directly with the magnitude and timing of investment costs. A high ROI means that investment gains compare favourably to investment costs. The advantages of the ROI method are that it is simple to compute and it is a familiar concept in the business community.

Net Present Value (NPV)

NPV is a discounted cash ﬂow (DCF) analysis that compares the amount invested today to the present value of the future cash receipts from the investment. In other words, the amount invested is compared to the future cash amounts after they are discounted by a speciﬁed rate of return. NPV discounts all of the cash ﬂows of a project to a base year. These cash ﬂows include, but are not restricted to, equipment costs, maintenance expenses, energy savings, and write-off values. The cash ﬂows are discounted to reﬂect their time value. Once all of the cash ﬂows are discounted to a base year, the cash ﬂows are weighed on a common basis and can be added together to obtain a ‘total net present value’. A positive net present value indicates an acceptable project. A negative NPV indicates that the project should not be considered.

Proﬁtability Index (PI)

The proﬁtability index, or PI, (also known as a beneﬁt/cash ratio [B/C] or savings/investment ratio [SIR]) compares the present value of future cash inﬂows with the initial investment on a relative basis. Therefore, the PI is the ratio of the present value of cash ﬂows (PV) to the initial investment of the project.

Present Value of Future Cash Flows

Initial Cost Investment

PI =

A PI of 0.75 means that the project returns currency in present value for each current currency invested. In this method, a project is accepted if PI > 1 and rejected if PI < 1.

Note that the PI method is closely related to the NPV approach. In fact, if the net present value of a project is positive, the PI will be greater than 1. In other words, if the present value of cash ﬂows exceeds the initial investment, there is a positive net present value and a PI greater than 1, indicating that the project is acceptable.

Internal Rate of Return (IRR)

An internal rate of return is also a discounted cash ﬂow (DCF) analysis commonly used to evaluate the desirability of investments or projects. The IRR is deﬁned as the interest rate that makes the net present value of all cash ﬂow equal to zero. In ﬁnancial analysis terms, the IRR can be deﬁned a discount rate that that makes the present value of estimated cash ﬂows equal to the initial investment. The higher a project’s internal rate of return, the more desirable it is to undertake the project.

MP Steam

HP Steam

Letdown

Condensate

Boiler

Steam

Turbine

Steam

Turbine

Making a Step-change: Opportunities, Auditing and Improvement Projects

Assuming all other factors equal amongst the various projects, the project with the highest IRR would probably be considered the best and undertaken ﬁrst. IRR should not to be confused with the ROI method which calculates the rate of return that an investment is expected to yield. IRR expresses each investment alternative in terms of rate of return, a compound interest rate.

Discount Rate

An important element of DCF analysis is the determination of the proper discount rate that should be applied to bring the cash ﬂows back to their present value. Generally, the discount rate should be determined in accordance with several factors: Project risk, Project Size and Life, Time Horizon, Different Cash Flows, tax considerations, etc. This is a specialised area and consultation with the Site/Company economist should take place in selecting an appropriate discount rate for the projects in question.

Making a Go/No-Go Project Decision

The following are 4 generic guidelines to make better investment decisions:

1. Focus on cash ﬂows, not proﬁts. Keep as close as possible to the economic reality of the project. Accounting proﬁts contain many kinds of economic anomalies, ﬂows of cash, on the other hand, are economic facts.

2. Focus on incremental cash ﬂows. Focus on the changes in cash ﬂows affected by the project. The analysis may require some careful thought: a project decision identiﬁed as a simple go/no-go question may hide a subtle substitution or choice among alternatives.

3. Account for time. Time is money. According to the theory of time preference, investors would rather have cash immediately (sooner than later). Use NPV as the technique to summarise the quantitative attractiveness of the project.

4. Account for risk. Not all projects present the same level or risk. One wants to be compensated with a higher return for taking more risk. The way to control for variations in risk from project to project is to use a discount rate to value a ﬂow of cash that is consistent with the risk of that ﬂow.

9.4.2 Utilities Marginal pricing

Typically a company will maintain a set of product values used for capital project estimation, perhaps including quality premiums and so forth. However Utilities systems, and in particular multi-level steam networks, can provide a challenge when looking at the pricing of utilities streams for project evaluation. In most locations there are various operational routes available (say) to generate an extra tonne of steam. Historical average costs should not be used as these do not reﬂect the different efﬁciencies of production, current constraints and what may be available at the time.

Consider a simple 2-level steam network as illustrated. There are two ways to value MP Steam. The value of MPS generated through the letdown station is essentially

Making a Step-change: Opportunities, Auditing and Improvement Projects

the value of HP steam adjusted for the enthalpy difference of HP/MP steam. However the value of MP steam generated through the steam turbine is the value of HP steam minus the power generation. Thus the value of MP steam from both these routes are different and not the same as the average MP steam cost.

This is an important consideration and requires understanding of which constraints are active when allocating utility prices. In reality it will be more complex than the simple example quoted here – multiple turbines with differing efﬁciencies – multiple steam levels etc.

The use of marginal economics:

• Differentiates between different levels of producing steam

• Provides the necessary signals to allow optimisation of the steam network

• Provides the actual value of energy saved when carrying out efﬁciency projects

• However, is it dynamic – as fuel prices or site demand proﬁles change relative to the active utilities constraints then so do the marginal costs

This nicely illustrates the potential beneﬁt of an on-line Utilities Optimisation system which will recognise the current constraints and what is affecting the marginal pricing and make operational decisions on the pertinent pricing strategy.

9.4.3 Investment Thresholds for Energy Projects

Traditional investment criteria have not always served energy efﬁciency projects well; short term productiondriven investments can appear more attractive than longer term energy projects which recoup their beneﬁts over many years. In the current difﬁcult economic climate where capex budgets are limited energy efﬁciency projects can slip in priority against ‘must do’ safety or product related investments.

To mitigate these effects companies are increasingly turning to special investment criteria for energy proposals which better reﬂect the longer term nature of such projects. Thus whilst a Proﬁtability Index threshold of (say) 4 may be needed for normal projects a threshold of 2 may be used for energy projects.

Such a philosophy is reﬂected in the Carbon Trust Energy Maturity Matrix (Appendix B) where “positive discrimination in favour of ‘green’ schemes...” is rated as Best Practice.

Example. Company X (a large reﬁnery/petrochemical site) had a big surplus of Low Pressure Steam (LPS) – the constraint was on Medium Pressure Steam (MPS). Hence a traditional utilities pricing approach gave zero value to LPS - there was no apparent beneﬁt in saving LPS. However this was counter-intuitive to operational and engineering common sense – it implied that there was no ﬁnancial beneﬁt in repairing steam leaks. So, in conjunction with the Site Economist, an agreed LPS value was chosen which provided an incentive to a steam leak repair programme. In parallel with this project activities aimed at rebalancing the MPS/LPS distribution helped accommodate as much as possible of the ‘saved’ LPS.

Common Energy Tools and Techniques

10 Common Energy Tools and Techniques

A list of comprehensive energy efﬁciency techniques covering all industries is beyond the scope of this book – the reader is directed to sector-speciﬁc literature such as the EU Best Available Techniques which are speciﬁcally written for each sector (Steel, Pulp and Paper, Oil, Textiles, etc. – refer to Appendix G).

However there are some generic best practices which do have widespread applicability across the chemical and process industries and are likely to occur in the majority of energy improvement plans. These are basic good practice and are presented here as an overview. Detailed implementation advice can be found in many standard texts and manuals.

10.1 Measurement and Control of Energy Streams

Accurate measurement of energy streams and good control of energy-inﬂuencing parameters is an absolute essential foundation for nearly all energy improvement initiatives. Indeed it is probably one of the most effective means of improving energy efﬁciency.

Chapter 6 on Energy Management Information Systems discusses in some detail the role of energy information in decision-making. The foundation of this is an effective and comprehensive set of measurements. Unfortunately, at times in the past, the provision of energy measurements was often sacriﬁced during plant design as an economy measure. Similarly measurement provision on package units such as turbines was left to the vendor’s local package and not fully integrated into the plant instrumentation system. Thus it is quite common for an energy project to require additional instrumentation. In this respect the growth of wireless instrumentation in recent years has made the retroﬁtting of measurement points a more economical prospect. Local gauges and thermowells can now easily be brought back to the control room/DCS.

10.1.1 Mass and Energy Balances

Being able to construct an energy balance around the manufacturing unit in question is a basic element in the reporting and analysis of energy data. It allows an understanding of the distribution of energy consumption and loss across the unit and is the base line for identifying opportunities for improvement. When monitored in real-time it provides the basis for the calculation of energy reports, KPIs and the consequent identiﬁcation of changes in operation. High quality measurement of the energy streams (i.e. enthalpies) is essential.

In some cases – for instance the loss of energy through an air cooler, it is clearly not possible to directly measure the energy lost to atmosphere. In such cases it will need to be calculated by difference from an energy balance around the equipment in question.

Common Energy Tools and Techniques

Looking at the four main classes of energy involved:

10.1.1.1 Feed and Product streams

The key is accurate and comprehensive ﬂow measurement of all incoming and outgoing feed and product streams. When constructing energy balances the calibration conditions for the ﬂow measurements should be checked. In calculating stream enthalpies the correct operating temperature should be used for the speciﬁc heat values. If there are wide variations in operating temperatures (different modes) then temperature compensation can be considered. (For example the speciﬁc heat of a typical light oil product changes from 0.625 to 0.675 kcal/kg.°C as the temperature rises from 150 to 200 °C). So attention to such details is important. In the case of gas ﬂow, pressure compensation may be appropriate.

10.1.1.2 Steam

The key issues around steam measurement involve the correct installation (to prevent condensate problems) and (when appropriate) suitable corrections for the effect of changes in temperature and pressure. There is a host of instrumentation available for both steam (and air ﬂows), however the two predominant technologies are Vortex and Differential Pressure derived ﬂow using primary elements (oriﬁce plates, pitot tubes, nozzles). The advancement of DP ﬂow technology now allows for Multivariable Transmitters that can measure the differential pressure (volumetric ﬂow), static pressure and temperature all within the one instrument. Thus the instrument is able to calculate fully compensated mass ﬂow of steam as well as the energy content of steam. When used with an Annubar (pitot tube) the permanent pressure loss is negligible and the installation costs are a fraction of in-line ﬂow meters (requiring only one mounting nozzle to be welded in place and one entrance in to pipe medium).

10.1.1.3 Fuels

As well as the obvious need for accurate ﬂow measurement, for which a lot of the previous comments apply, an important factor for fuels is the caloriﬁc value of heating value of the fuel. If the fuel is of a consistent composition – e.g. externally purchased fuel oil or natural gas then a ﬁxed factor can be used. Internal fuel gas systems with a variety of fuel sources are much more likely to subject to swings in caloriﬁc value. In such cases on-line compensation by a relative density meter on the fuel gas supply can make a signiﬁcant improvement in accuracy. In general for similar types of gases heating value reduces as molecular weight increases. Turndown issues should also be considered – especially if square root/DP type ﬂow measurements are used. Double-range transmitter systems may be appropriate.

Benefit

Common Energy Tools and Techniques

10.1.1.4 Electrical Power Measurements

Most process plants control electrical motor driven assets from a Motor Control Centre (MCC) via the system controls. Many are ﬁtted with electrical power meters from which the respective electrical power consumed by the asset can be monitored and recorded. Where this provision is not in place the use of clamp-on electrical transducers and permanent hardwired sensors can be used. There are literally hundreds of transducer sensor types available for measuring current and voltage and hence determination of electrical power.

10.1.2 Process Control

As with many other considerations; quality, yield or reliability, good control is an essential prerequisite for energy efﬁcient operation. Being able to run in a robust and stable operation close to an operational constraint is important as is the ability to shift operation in a controlled manner as external factors change thus always running at the energy efﬁcient spot.

104

102

% of Limit

Specification or Limit

100

Poor Control Improved Control Average (Setpoint)

moves closer to limit

Base Case Stabilise Exploit

Distribution of Instantaneous Values

The concept of improved stability allowing a constraint to be approached more closely is illustrated: the increased stability allows the average operating point to be moved closer to an operational target or constraint without infringing the limit. And this results in less waste and a reduction in operating costs. So, for instance, a furnace with good quality combustion air control can safely run closer to an ideal low stack oxygen target without the risk of dangerous substochiometric ﬁring, thus saving fuel. Or a distillation column can run closer to its ideal reboil duty and still consistently produce on-speciﬁcation products without the need to over-reboil or over-reﬂux (more energy) to play safe.

Typical generic control techniques that play a part on energy efﬁcient operation follow:

10.1.2.1 Controller Tuning and Basic Set-up.

The base-level control loops, typically 2 or 3-term PID controllers, are the basic manipulation handles of the plant and need to be able to operate reliably and consistently. Without them any amount of higher level energy-saving control will not function.

All controllers should be periodically reviewed – a simple observed set-point step test is sufﬁcient. We are looking ideally for what is known as Quarter Amplitude Damping in the response to a set-point change.

Step response for sound controller settings

Common Energy Tools and Techniques

Otherwise performance will be either too sluggish or over-reactive.

Controller re-tuning is a well-documented activity –

a = overshoot b = undershoot

methods such as Ziegler-Nichols and Cohen-Coen are well known and will be found in many textbooks and guides. Tuning packages which run on PCs are widely available although manual observation with a wristwatch and notebook can be as effective. Many modern DCS have self-tuning packages. These can be very useful although their use in a continual background mode is debatable.

At the same time valve operation and instrument range should be checked – controllers running with valves consistently wide-open or almost shut will not perform well – and similarly instruments that are operating at the extreme ends of their range will not provide consistent and accurate measurements. Re-ranging transmitters and valve trims may be needed.

Finally, for master-slave systems, the master should always be tuned slower than the slave controller.

10.1.2.2 Feed-Forward Control

For most manufacturing processes there is a proportionality between energy consumption and feedrate – the more feedstock you process the more energy is required. The precise nature of this relationship may be non-linear with signiﬁcant ﬁxed loads but the basic proposition is generally a good starting point.

Hence for plants where there are regular feedrate changes then feed-forward control plays an important part in keeping energy consumption down.

This is particularly important for the ﬁnal process energy consumers. Whilst on many units the Utilities complex is the largest single direct energy consumer and receives, quite rightly, the focus of attention, it is also important that the subsequent consumption of that utility-generated energy by the process users is tightly controlled. This is the actual energy going into the manufacturing process.

In execution feed-forward mechanisms may vary from a simple ratio system through to a disturbance variable as part of a multivariable model-based controller (see below) at the other. Dynamics do have to be considered. If the feedrate measurement that is being used to drive the system is physically far ahead in the process then it may be appropriate to include some dynamic compensating term (typically a ﬁrst order lag) to prevent “premature” movement of the slave loop before the ﬂow changes have worked their way through the process. Of course the overall loop needs to have a feedback mechanism to allow operator adjustment to adjust product quality (e.g. changing the reboil/feed ratio on a distillation column).

Other, less explicit, forms of feed-forward control can be considered to handle disturbances in a predictive manner. This includes use of heat duty controllers (as opposed to ﬂow controllers) for heating systems (e.g. reboilers) which will compensate for variations in the heating medium temperature. Or corrections for the heating value of fuel gas or steam conditions. All these allow a more accurate setting of heat input without having to allow wasteful contingency factor.

90%

Common Energy Tools and Techniques

10.1.2.3 Constraint pushing control

Constraint pushing recognises that there are often extra degrees of freedom in unit operation which can be exploited to achieve a secondary control aim over and above the basic regulatory structure. This is particularly important from an energy perspective when driving the plant towards an energy efﬁcient position and is a desirable outcome although not necessarily at the expense of quality or safety considerations.

It can also be used where high speed regulatory control is the ﬁrst aim and then slower constraint control adapts operation to a more efﬁcient position whilst maintaining primary controllability. Typical of these are valve position controllers which are useful ways of continually pushing operation to a low energy position without losing tight control. The aim being to operate with the valves in question at about 90% open. Three examples illustrate this as follows:

Floating Pressure Control in a Distillation Column. It is well known that, within hydraulic constraints, distillation columns require less energy to achieve the same separation as the pressure is reduced. However at any one time stable control of the column pressure is desirable to assist consistent product separation. The lowest pressure will generally be

VPC

achieved when the overhead condenser is running at maximum duty – i.e. the output of the Pressure Controller which drives the condenser is at a maximum. So a constraint controller can be added to the basic design which manipulates the pressure controller setpoint such that its output is ideally 90%. This is a slow acting controller which will make small and gradual adjustments to reduce the pressure controller setpoint

FC FC

thus allowing the pressure control to always maintain stable basic control.

(Normally such a system will require pressure compensated temperatures and adjustment of reboil heat to match the constraint pusher and correspondingly minimise the heat input).

Valve networks and Variable Speed Drives. Operating control valves at 50% open or less is wasteful as hydraulic energy from a pump is being wasted in the high pressure drop over the valve. Consider the distribution network illustrated. A steam driven compressor supplies several consumers all on ﬂow

VPC

control. There is clearly the potential for a large turndown and spread of operation.

Steam

So again the use of a valve position controller is suggested which monitors the position of the control valves in a network and then slowly drives the turbine

BFW

Common Energy Tools and Techniques

speed down such that the widest open valve is at 90%. This is an excellent means of tuning down the compressor energy consumption whilst maintaining good ﬂow controllability.

Similar examples could be considered using a variable speed drive on electric pumps or controlling a common Hot Oil furnace which supplies several independent consumers.

Exchanger preferential control. In the similar manner there may be choices in balancing heat exchanger networks as the relative duties and operation of the exchangers change in line with varying operations. Consider the illustrated situation of a process stream which is cooled against a process exchanger (Q a Boiler Feed Water heater (Q

) and a Cooling Water trim cooler (QCW). High speed control of the exit

BFW

temperature is provided by manipulating the valve to QCW. Flow variations through QP and Q

are

decoupled by the Pressure Differential control across the exchanger bank which sets the balancing ﬂow through Q

BFW

Hot Cold

VPC

10%

PDC

Prod

BFW

However it is desirable that as much heat as possible is recovered by Q controller looks at the signal to the Q setpoint so as to minimise the ﬂow through Q be decreased so as to divert ﬂow through Q

valve and manipulates the Pressure Differential Controller (PDC)

: if the QCW valve opens too much the setpoint to the PDC will

which is economically more attractive.

BFW

. Thus a valve position or constraint

BFW

The above examples indicate the relatively simple options that can be built around this concept. The relative operation of a wide variety of equipment and processes can and will change on a continual bases and such techniques are very useful in keeping the process in a sensible, energy efﬁcient, area of operation.

10.1.2.4 Model Predictive Control (MPC)

The aforementioned techniques are all built using conventional control components which are widely available in either pneumatic control, single loop electronic or DCS. The basis is the 3-term PID controller.

However all of the above can be combined in a single algorithm set. Over the last 25 years model-based control has been increasingly used in the process industries. There are many well-known algorithms sold

Fuel Pressure

Common Energy Tools and Techniques

through a variety of system and consultancy suppliers – PredictPro, DMC, SMOC, RMPTC etc – all of which follow a common basic philosophy.

The controller structure envisages a set of controlled variables (plant targets- e.g. product qualities) and a set of manipulated variables (plant handles - ﬂows, valves and other base level controllers) plus associated disturbance (i.e. feed-forward) and constraint (limiting) variables. Dynamic models (typically 1st or 2nd order) are established between the variables in a fully predictive multivariable manner. At each control cycle a linear optimisation routine calculates an optimum set of manipulated variable signals so as to meet the controlled variable set-points and honour any constraints and disturbances. It is sometimes also possible to include an economic objective function which can move the plant towards a given goal if there are sufﬁcient degrees of freedom available.

Fuel Supply

Opacity

ID Fan

FD Fan

Steam Flow

Emissions

Oxygen Fuel Flow

Heat Release

Calculation

Logic

Total

Airflow

Boiler

Constraints

CV Adjust

Fuel 1

Master

Fuel

Valve

Header

Pressure

Steam

Boiler Master Operation

Air 1

Master

Air

Damper/VSD

Boiler

MPC

EMS

Fuel 2

Master

Valve

Flow

Fuel Optimiser

Fuel

Boiler

Warm-Up

Air 2

Master

Air

Damper/VSD

Fuel Cost

Calculations

Fuel

Restraints

Constrained Demand to other Fuel Masters

CV Range

Oxygen ID Fan

Initially such applications were on a smaller scale – say a 4x4 controller on a single distillation column. Nowadays much larger plant-wide matrix sizes, up to 40x40 variables or greater, have been built. They play a very useful role in energy efﬁciency as their multivariable constraint handling can better handle an energyminimisation objective or constraint than the traditional single input/single-output feedback controller.

Such controllers have proven very successful in reducing energy costs, in particular for processes such as distillation where energy savings of >5% are typically reported (in addition to yield and quality beneﬁts). However they require specialist skills for design, implementation and support. It may be better consider implementation as part of a larger quality improvement or debottlenecking project than purely for energy considerations.

Feed Water

Live Steam

Flue-Gas

Heat Consumer

Common Energy Tools and Techniques

10.2 Utilities Systems

Steam is probably the most common utility medium for manufacturing sites (others being tempered water and thermal fuels). Most sites will generate steam in boilers at a high pressure and then let down via compressors, pumps, turbo-alternators and consumers to generate electricity and meet process and pumping needs. Typically sites will have a two or three level steam hierarchy. Two broad areas of attention deﬁne the focus for energy efﬁciency:

• Efﬁciency of generation – the Boiler House

• Distribution and matching demand – the steam network

10.2.1 Steam Generation

Boiler ﬁring will be considered as part of the general combustion discussion in section 10.3. However given the size of many steam generating systems – providing site-wide steam to many plants – there is signiﬁcant scope for optimisation of the boiler operation, in particular the water-side activities. Large circulating energy streams are involved – often at relatively low temperature levels. Corrosion and water quality issues play an important part and thus provide a delicate balancing act for the Boiler conﬁguration and operation.

10.2.1.1 Boiler Feed Water Preheat

The Boiler Feed Water from the deaerator (BFW) being returned to the boiler generally has a temperature of approximately 105 °C. The water in the boiler (at a higher pressure) will be at a higher temperature. The boiler is fed with water to replace system losses and recycle condensate, etc. Heat recovery is possible by preheating the feed-water, thus reducing the steam boiler fuel requirements.

Boiler

Feed-Water

Container (2)

De-Aerated

Reheating is achieved in several ways:

Feed-Water Preheating

with Waste Heat

Economiser (1)

De-Aerated Feed Water

Condensate

Tank (3)

Steam

Turbine

Condenser

• Using waste heat (e.g. from a process): BFW can be preheated by available waste heat. This is an excellent way of recovering low level process heat e.g. from product rundown streams

• Installing an economiser (1) – i.e. heat exchange of boiler ﬂue gases to BFW

Common Energy Tools and Techniques

• Using deaerated feed-water: in addition, the condensate can be preheated with deaerated feedwater before reaching the feed-water vessel (2). The BFW from the condensate receiver (3) has a lower temperature than the deaerated feed-water from the feed-water container. Through a heat exchanger, the deaerated feed-water is cooled down further (the heat is transmitted to the feed-water from the condensate tank). As a result, the deaerated feed-water forwarded through the feed-water pump is cooler when it runs through the economiser. It thus increases its efﬁciency due to the larger difference in temperature and reduces the ﬂue-gas temperature and ﬂue-gas losses. Overall, this saves live steam, as the feed-water in the feed-water container is warmer and therefore less live steam is necessary for its deaeration

In practice, the possible savings from feed-water preheating amount to several per cent of the steam volume generated. Therefore, even in small boilers the energy savings can be in the range of several GWh per year. For example, with a 15 MW boiler, savings of roughly 5 GWh/yr, some EUR 60000/yr and about 1000 tonne CO

/yr can be attained. Boiler ﬂue-gases are often rejected to the stack at temperatures of

more than 100 to 150 °C higher than the temperature of the generated steam. Generally, boiler efﬁciency can be increased by 1% for every 20 °C reduction in the ﬂue-gas temperature. By recovering waste heat, an economiser can often reduce fuel requirements by 5 to 10% and pay for itself in less than 2 years.

10.2.1.2 Deaerator operation

Deaeration protects the steam system from the effects of corrosive gases by removing dissolved gases from boiler feed-water. It accomplishes this by reducing the concentration of dissolved O

and CO2 to a level

where corrosion is minimised. A dissolved oxygen level of 5 parts per billion (ppb) or lower is needed to prevent corrosion in most high pressure (>13.79 barg) boilers. While O

concentrations of up to

43 ppb may be tolerated in low pressure boilers, equipment life is extended at little or no cost by limiting the oxygen concentration to 5 ppb. Dissolved CO

is essentially completely removed by the deaerator.

The design of an effective deaeration system depends upon the amount of gases to be removed and the ﬁnal gas (O

) concentration desired. This in turn depends upon the ratio of BFW makeup to returned

condensate and the operating pressure of the deaerator. Sudden increases in free or ‘ﬂash’ steam can cause a spike in deaerator vessel pressure, resulting in re-oxygenation of the feed-water. A dedicated pressure regulating valve should be provided to maintain the deaerator at a constant pressure.

Steam to the deaerator provides physical stripping action to scrub out unwanted gases and heats the mixture of returned condensate and boiler feed-water makeup to saturation temperature. Steam ﬂow may be parallel, cross, or counter to the water ﬂow, bubbling through the water, both heating and agitating. Exit steam is cooled by incoming water and condensed at the vent condenser. Non-condensable gases and some steam are released through the vent. Most steam will condense, but a small fraction (usually 5 –14%) must be vented to accommodate the stripping requirements. Normal design practice is to calculate the steam required for heating, and then make sure that the ﬂow is sufﬁcient for stripping as well. If the condensate return rate is high (>80%) and the condensate pressure is high compared to the deaerator pressure, then very little steam is needed for heating, and provisions may be made for condensing the surplus ﬂash steam. Optimisation of the deaerator pressure and vent rate is an important energy-saving consideration.

The energy in the steam used for stripping may be recovered by condensing this steam and feeding it through a heat exchanger in the feed water stream entering the deaerator.

Common Energy Tools and Techniques

Deaerator steam requirements should be re-examined following the retroﬁt of any steam distribution system, condensate return, or heat recovery energy conservation measures. Continuous dissolved oxygen monitoring devices can be installed to aid in identifying operating practices that result in poor oxygen removal.

Note - the deaerator is designed to remove oxygen that is dissolved in the entering water, not in the entrained air. Sources of ‘free air’ include loose piping connections on the suction side of pumps and improper pump packing.

10.2.1.3 Minimising Blowdown

Minimising boiler blowdown rate can substantially reduce energy losses as the temperature of the blowdown is directly related to that of the steam generated in the boiler.

As water vapourises in the boiler, dissolved solids are left behind in the water, which in turn raises the concentration of dissolved solids in the boiler. The suspended solids may form sediments, which degrade heat transfer. Dissolved solids promote foaming and carryover of boiler water into the steam. In order to reduce the levels of suspended and dissolved solids (TDS) to acceptable limits, two procedures are used, automatically or manually in either case:

• Bottom blowdown is carried out to allow a good thermal exchange in the boiler. It is usually a manual procedure done for a few seconds every several hours

• Surface or skimming blowdown is designed to remove the dissolved solids that concentrate near the liquid surface and it is often a continuous process

• The blowdown of salt residues to drain causes further losses accounting for between one and three percent of the steam employed. Further costs may be incurred for cooling the blowdown residue to the temperature prescribed by regulatory authorities. The amount of energy lost by blowdown increases with higher boiler pressures

• In order to reduce the required amount of blowdown, there are several options:

• Condensate Recovery. Condensate is already puriﬁed and thus does not contain any impurities concentrated inside the boiler. If half of the condensate can be recovered, the blowdown can be reduced by 50%

• Water Treatment. Depending on the quality of the feed-water, water softeners, decarbonation and demineralisation might be required. The level of blowdown is linked with the level of the more concentrated component present or added to the feed-water. In case of direct feed of the boiler, blowdown rates of 7 to 8% are needed; this can be reduced to 3% or less when water is pre-treated

• The installation of automated blowdown control systems can also be considered, usually by monitoring conductivity. The blowdown rate will be controlled by the most concentrated component knowing the maximum concentration possible in the boiler

• Flashing the blowdown at medium or low pressure is another way to recover the energy content of the blowdown. This solution can be more favourable than exchanging the heat in the blowdown via a heat exchanger

Pressure degasiﬁcation caused by vapourisation also results in further losses of between 1 and 3%. CO and O

are removed from the fresh water in the process. This can be minimised by optimising the deaerator

vent rate. The amount of waste water will also be reduced if blowdown frequency is reduced.

Common Energy Tools and Techniques

10.2.1.4 Condensate Collection and Heat Recovery

Where heat is applied to a process via a steam heat exchanger, the steam surrenders energy as latent heat as it condenses to hot water. This water is either lost or recycled to the boiler. Re-using condensate has four objectives:

• Recycle the energy contained in the hot condensate

• Saving the cost of the (raw) top-up water

• Saving the cost of boiler water treatment

• Saving the cost of waste water discharge Condensate is collected at atmospheric and vacuum. The condensate may originate from steam in appliances at a much higher pressure. Where this condensate is returned to atmospheric pressure, ﬂash steam is spontaneously created. This can also be recovered. Deaeration is necessary in the case of vacuum systems.

The technique is not applicable in cases where the recovered condensate is polluted or if the condensate is not recoverable because the steam has been injected into a process. For new designs, good practice is to segregate the condensates into potentially polluted and clean condensate streams. Clean condensates are those coming from sources which, in principle, will never be polluted (for instance, reboilers where steam pressure is higher than process pressure, so that in the case of leaking tubes, steam goes into the process). Potentially polluted condensates are condensates which could be polluted in the case of an incident (e.g. tube rupture on reboilers where process-side pressure is higher than steam-side pressure). Clean condensates can be recovered without further precautions. Potentially polluted condensates can be recovered but need segmentation options in the case of pollution which is detected by online monitoring, e.g. Total Organic Carbon (TOC) meter.

Condensate recovery has signiﬁcant beneﬁts and should be considered in all applications. The use of pinch analysis (see 10.5) for water systems has proven [particularly effective.

10.2.2 Steam Networks and Distribution Optimisation

The successful efﬁcient operation of a site steam network can be a major challenge and presents signiﬁcant opportunities to both waste (or gain) valuable energy as one attempts to balance supply and demand. Typically a manufacturing site may have 2 or 3 levels of steam networks at different pressures, a collection of boilers, turbo-alternators, and let-downs in addition to the process consumers. Some turbines may be total condensing, some may be back-pressure turbines. It is very likely that the network will have grown over the years – new equipment will have been added to relieve a particular historical constraint at a moment in time. Circumstances change and a different set of constraints will now apply. There may be different fuel options: gas, liquid, waste gas. More dynamic considerations could include time-dependent fuel and electricity tariffs (peak/off-peak).

Such a scenario can all too often result in a constrained situation where typically one steam level is limited and the other is in surplus. There may be some opportunity for balancing this dynamically by control and optimisation techniques, it may need some structural changes to bring the system into balance.

Feeds Products Waste Water

Power Import/Export

Common Energy Tools and Techniques

Fuel Import Water

Gas

System

Process

Product

Fuel

Process

Utility System

Process

ProductProduct

Side

Product

Process

FeedFeed Side

Water

System

Production System

10.2.2.1 Utilities Optimisation

For any system which has degrees of ﬂexibility (e.g. alternate options to generate electricity, differing equipment efﬁciencies, varying load proﬁles) then a utilities optimisation package can prove very useful. It may be an off-line package run in simulation mode or a fully closed-loop real-time optimiser driving the setpoints of the base level controllers around the system.

Typically a model is built of the key utilities components – turbines, boilers, letdowns and desuperheater stations. This will be ﬁtted to the current operational conditions and process utility requirements – making the base case or “as is” model. This done, the model will run in conjunction with a mathematical optimisation package which will make adjustments to the ﬁtted model (in the form of new ﬂows, allocations between turbines, letdown streams etc) so as to minimise a cost function – i.e. the economic cost of delivering the required process utility consumption at that moment. Thus as operating demand, or fuel/ electricity prices or equipment performance (fouling) changes then a more economical solution is sought. More advanced packages can handle discrete optimisation steps such as pump drive changes (steam-electricity) and other step-wise changes.

Motive Steam (PI)

Discharge (P)

Principle of Thermo Compressors

Performance:

E=PI/PO Expansion Ratio

K= P/PO Compression Ratio

Project:

E=18 bara/4.5 bara=4

K=8 bara/4.5 bara=1.8

Performance of Thermo Compressor

K=P/PO Compression Ratio

MPS/LPS=3/1

Common Energy Tools and Techniques

10.2.2.2 Structural changes - Steam blending

Signiﬁcant structural imbalances in steam systems cannot always be handled by real-time control – the imbalance may be simply too large. In this case the site has to turn to changes in the hardware and equipment conﬁguration to bring the system nearer to balance.

Many examples are obvious – changing steam and electric drives, adding a package boiler, condensing/ backpressure turbine swaps and so forth. A technique

Suction (PO)

which deserves more notice is the use of steam thermocompressors to ‘blend’ two levels of steam to achieve an intermediate level (rather than let all the steam down from the higher pressure level).

Consider a process steam application, for instance reboil steam to a column. The process requires steam at 8 bara to meet the correct saturation temperature. The steam levels on site are 18 bara and 4.5 bara so normally the steam would be taken from the 18 bara system and letdown to 8 bara through the normal reboiler steam control valve. The 18 bara system is limited and the 4.5 bara steam is in surplus (a common situation).

However by blending together a mixture of 18 and 4.5 bara steam in a thermocompressor the required 8 bara steam can

E=2 E=4

E=50

be achieved using less of the (expensive) constrained 18 bara steam and making this up with surplus (cheap) 5 bara steam. In the case quoted about one third of the total steam mass ﬂow was shifted from 18 bara

Specific Steam

Consumption

K=1.8

to the 4.5 bara supply.

10.3 Combustion Activities

For probably the majority of process industry sites ﬁred equipment represents the largest single source of energy transformation. Whether it be as direct process furnaces or as part of Boiler House and Utility complexes generating steam and electricity for subsequent use on site, the effective operation and control of ﬁred equipment plays a major role in tackling energy efﬁciency. As always there are many issues needing attention. Whilst this User Guide does not set out to be a detailed manual on Combustion Engineering the following topics may serve as reminders of the common priority areas which need to be considered as part of energy efﬁcient operation. Furnace operation can easily slip out of tune – there are many considerations – installed equipment, operational procedures, control, setup, maintenance – all of which have a direct and interrelated impact on furnace efﬁciency. Furnaces are potentially highly unsafe pieces of equipment yet also present a signiﬁcant opportunity for energy saving. Thus care and attention is needed to ensure efﬁcient but safe operation.

Stack Temperature Deg.C

Furnace Efficiency Curves

Furnace Efficiency

Common Energy Tools and Techniques

10.3.1 Installed Equipment

Replacing/modifying furnaces can be a major capital expense and not undertaken lightly. However, for a large process furnace or boiler, perhaps burning 10s or 100s of tonnes of fuel a day, relatively small improvements in efﬁciency can turn into major fuel savings.

10.3.1.1 Upgrade natural draught to forced draught operation

Whilst most large furnaces installed in recent years will be modern forced draft furnaces there are still many older natural draught furnaces in operation, perhaps installed at times or in locations where energy prices were lower or as part of a package unit. The combination of relatively high stack oxygen contents and typically poor ﬂue gas heat recovery mean that furnace efﬁciencies of perhaps 50-60% are typical. Thus there is the potential to increase furnace efﬁciency by up to another 25% representing major savings in fuel.

10.3.1.2 Improved combustion air-preheat

The recovery of waste heat from furnace ﬂue gases and using it to preheat combustion air is one of the most effective ways of improving furnace efﬁciency. A rule of thumb – 20 °C reduction in stack temperature will result in 1% improvement in furnace efﬁciency. Thus 2 questions need to be asked: is an effective air-preheater in place and secondly is it well maintained (e.g. regularly cleaned) to ensure maximum heat transfer.

There are many forms of ﬂue-gas recovery and air preheat. Local physical

(assuming 5% radiant losses)

100

100 200 300 400 500 600 70

1% O 3% O 5% O 10% O

considerations (space, pressure drop) will play a large role in the ﬁnal selection. Direct heat exchange or indirect exchange by pressured water (Liquid Coupled Air

Preheater) are possible. Older types such as the famous Llungstrom airpreheaters using rotating plates are not so fashionable these days and are maintenance heavy. Indeed an air-preheater upgrade may be an attractive project. Fuel-type and fouling considerations may play a major role in type-selection; there are pros and cons for most types. The main

limit to operation is the constraint on how low the ﬂue gases may be cooled. Depending on fuel type this may be typically 150 °C as below this point dew-point corrosion in the ﬂue can be an issue. (Locations burning their own fuel gas should take care here as such gases can sometimes contain other by-product compounds not found in normal natural gas which produce undesirable combustion products e.g. smuts).

Of course other options to recover ﬂue gas heat include waste heat boilers and other process or heat recovery mechanisms.

Regular cleaning of convection banks and air preheaters is essential, both as a daily operational procedure (sootblowing) and periodically through specialist cleaning (chemical, acoustic, jetting,...).

Common Energy Tools and Techniques

PPM Combustibles (CO+H

)

Gas

10.3.1.3 Burner upgrades – low NOx and turndown

Consideration may be given to the type of burner installed. Traditional pressure-atomised fuel oil burners have limited turndown (3:1) and often poor particulates performance. These constrain the operating ranges, particularly when the smoking limit is approached. A change of fuel to natural gas, installation of a steamatomised burner or a more up-to-date design should allow closer operation to the efﬁcient norm. This really requires simultaneous attention to the control systems to provide the assurance and secure response that is needed to safely operate in these regions. Similarly if NO

emissions are a constraint a modern low-NOx burner

1000

800

600

400

200

0 1.2 2.4 3.6 4.8 6.0

Oil

Coal

Range of Optimum Efficiency

Percent O

should allow more efﬁcient furnace operation.

10.3.2 Furnace Control

Tight control of the fuel and combustion air systems is essential to safe and efﬁcient furnace operation. The balance between fuel and combustion air and the composition of the ﬂue gases is well known. As combustion air is reduced relative to the fuel ﬂow furnace efﬁciency improves primarily due to the fact that less air has to be heated to combust with the fuel. However the point at which incomplete combustion starts is the limit to how far this can be achieved. Beyond this, partly combusted fuels cause CO in the ﬂue gases to rise and operation becomes very inefﬁcient, dramatically increasing the risk of furnace explosions from unburnt fuel in the furnace box or convection bank.

However the point at which this happens is determined by many factors: the fuel type and composition, the quality of fuel atomization at the burner, register settings, air density and humidity. Many of these will change over time. Disturbances are possible. Thus high quality measurement and control of the fuel and combustion air systems plays a vital role on efﬁcient furnace operation.

10.3.2.1 Air and Fuel Measurement

Accurate measurement of air and fuel ﬂows are essential. Refer to section 10.1.1 for more details on measurement technology. Key issues for furnace measurements include:

• Quality installation of air measurement. Typically a venturi. Important that condensation effects in

instrument tappings are avoided

• Turndown considerations

• Fuel caloriﬁc value – ﬁxed, compensated, calculated?

10.3.2.2 Air-Fuel ratio control

The core to successful furnace operation is some form of air-fuel ratio control, perhaps automatically adjusted by the stack Oxygen content in a closed-loop fashion. There are many variations on the theme and a manual could be written on this one subject. Solutions include:

• Mechanical linkage between the air damper and fuel valve (increasingly rare and typically found on

small packaged systems)

Common Energy Tools and Techniques

• Straightforward ratio control which can be fuel-leading or air-leading

• Cross-limiting systems which limit the allowed fuel rate changes depending on the actual measured air-fuel-ratio (useful in cases of slow air-damper operation which can limit the responsiveness of the furnace/boiler)

• Closed-loop O

• Overall Stoichiometric control based on a stoichiometric back calculation of heat input. (particularly

control with limiting CO control

useful for high levels of unmeasured waste gas burning)

There is no single correct solution and as ever there is always a trade-off between complexity and beneﬁts. It is important to consider several factors in choosing the appropriate solution:

• Degree and speed of turndown and load ﬂexibility required (e.g. base-load vs. trim operation)

• Fuel-type and variability in composition

• Amount and variability of waste-gas ﬁring (if any)

• Availability of instrument/analyser resource for maintenance and support

10.3.2.3 Waste Gas Firing

Combustible waste gases, produced as by-products, are a common feature of many manufacturing locations – typically light gases produced as part of a catalytic reaction or distillation by-products. Two broad categories can be considered.

Gases with suitable pressure and composition (e.g. minimal inerts, no oxygen) are normally recovered in a centralised fuel gas system and burnt in a controlled manner as a distinct fuel on furnaces and boilers. The system may be topped up with (say) propane or butane to provide a fully ﬂexible fuel utility. This fuel would be treated as a conventional fuel and included in the air-fuel ratio systems. Perhaps density compensation may be applied to account for variations in heating value.

Other gases may be unsuitable for inclusion in fuel gas recovery, for instance gas produced at very low pressure levels. Gases may have large amounts of undesirable compounds in a fuel gas network. Historically such streams were either sent to ﬂare or may have been piped to a local furnace for incineration. However from an energy efﬁciency perspective these streams can have a signiﬁcant impact and need to be considered very carefully.

Two prime issues need to be considered: the recovery of useful energy from the waste gas and the impact of a ‘wild’ waste-gas stream on the controllability (and hence efﬁciency) of the furnace.

Small amounts of waste gas (with a potential heating value of up to say 5-10% of the furnace duty) can simply be piped into the furnace for incineration. Either a vented pipe or a waste gas spud burner will sufﬁce. The waste gas should be isolated as part of the furnace instrumented safeguarding function. The variations in ﬂow and heating value of this stream will be relatively small compared with the overall furnace duty and will be satisfactorily trimmed by the oxygen control feedback. Perhaps a simple ﬂow measurement added to the total fuel computation may help.

However beyond this level the relative impact of the waste gas is much higher and represents both a signiﬁcant potential fuel saving and also a control challenge. More advanced techniques such as the Emerson SmartProcess Boiler have been developed to tackle high levels of waste gas or other alternate

Common Energy Tools and Techniques

fuel ﬁring (e.g. from biomass). Here, the amount of air being consumed in the combustion process is continuously calculated from a measurement of the Excess Oxygen in the ﬂue gas. Air being consumed by the waste gas fuel is determined by calculating the air being used for auxiliary fuel and subtracting it from the total. From the air calculation, a determination of caloriﬁc value of the alternate fuel is made on an ongoing basis by calculating stoichiometric combustion and solving for Caloriﬁc Value. This is used to ratio fuel feed and other set points such that variations in the fuel are continually compensated for. Primary/ secondary or undergrate/overﬁre air ratios are automatically controlled to set points which are set based on load, characterization curves, the Excess Oxygen set point, and the waste gas fuel quality calculation. The alternate fuel delivery equipment is provided a set point based on load and the fuel quality calculation.

10.3.3 Furnace Operations – Training and Competencies

Thirty or Forty years ago operator responsibilities were quite different from that found today. Manning levels were generous, there was much less multi-tasking, local control buildings were scattered around a site (as opposed to the fully automatic and centralised control rooms of today). There was often a much greater divide between ‘inside’ and ‘outside’ operators. As a result operators often had distinct and long-lasting roles – pump-house operator, interceptor man and in the case of furnaces, dedicated ‘Firemen’ who worked full time on the furnace or boiler. These individuals built up real operational skills in their areas and that of furnace operator was particularly well developed.

Furnace operation is one of the few process industry areas where there is direct physical interaction with the process – it is possible to look through the sight tubes and make physical adjustments to the burners and registers to control the quality of combustion. That is still the case. And it is still an essential activity. However in the change to multi-tasking, centralised and ﬂexible operational roles, there has been a loss in some of these skills. Companies are now recognising the need to keep operators trained in operational combustion techniques and this has become part of many energy efﬁciency programmes.

Furnaces are dynamic pieces of equipment – fouling from the combustion process, varying loads, fuels and ambient conditions and the effects of high operating temperatures on machinery all conspire against stable operation. As a result clear daily operational responsibilities need to be deﬁned for furnace operation and this is backed up with practical training. The emphasis of this should be on the operational aspects – what can an operator do to correct and improve the reliable operation of the furnaces in his charge. Typical of the topics that should be covered:

• Draft Assessment - natural and forced draft – adjustment and correction

• Firing patterns – asymmetry

• Flame patterns and how to inﬂuence

• Register adjustment

• Impingement

• Safe start-up

• Burner changeover

• Leak identiﬁcation

• Sootblower and shotcleaning procedures

• Control of atomising steam

• Daily operational maintenance and checks

Common Energy Tools and Techniques

A good idea is to bring in an operational furnace expert for a dual exercise of furnace auditing (i.e. checking of the physical condition and the furnaces and burners) coupled with a practical hands-on operator training session. Linking his assessment of the furnace issues (and there will almost certainly be some) with the operational practices is a valuable exercise.

10.3.4 Maintaining Fired Equipment

Following on from the philosophy outlined in Chapter 8, Fired equipment should certainly be on the Energy Critical Equipment Register. As we have seen it plays a major role in a site’s energy consumption and poor maintenance can quickly lead to substandard and even dangerous operation.

As a start, the following basic maintenance activities should be determined, appropriate inspection and servicing periods deﬁned and the activities included in the maintenance management system:

• Servicing of sootblower/shotblasting equipment

• Periodic convection bank and air pre-heater cleaning

• Regular minimum stop checking and safeguarding system testing (Flame-eye testing)

• Burner conditions (tips and plugs)

• Fuel system – lagging and steam tracing

• Instrumentation checks (e.g. zero-checking transmitters)

• Stack analyser servicing (O

• Air damper operation

, CO, smoke density)

• Forced draft fan machine inspection and monitoring

• Burner air-register operation and lubrication

• Furnace shell leak inspection and repairs

• Refractory condition – including burner quarls

• Lagging inspection and periodic replacement

The above items all contribute to efﬁcient and reliable furnace operation. The list is by no means exhaustive but simply represents the activities that are relevant to the majority of process furnaces and boilers. A rule of thumb – 2% reduction in stack oxygen content will result in 1% improvement in furnace efﬁciency.

10.4 Maintenance in Support of Energy Efﬁciency

A recent in-depth energy audit and follow-up of a major European petrochemical site highlighted the impact of maintenance on energy efﬁciency. The site was established, mature and had experienced staff. The audit showed that in terms of installed energy efﬁciency technology and practices there was little to be gained. However the review identiﬁed major efﬁciency losses due to poor equipment maintenance. A concerted improvement programme identiﬁed and realised beneﬁts totalling 10% of the site’s energy consumption simply by repairing, cleaning and reinstalling existing facilities. The payback was less than 6 months.

Chapter 8 discusses the role of Work Processes supporting Energy Critical Equipment. Such a methodology would have prevented the decline in performance illustrated above.

Common Energy Tools and Techniques

Typical of the generic maintenance activities/techniques that will apply to many sites are:

10.4.1 Cleaning of Heat Transfer Equipment (including ﬁn-fans)

Many, if not most, processes lay down some form of fouling on heat transfer equipment – from high temperature reaction side effects, cokes and polymers through to biological fouling of cooling water systems. These all result in poorer heat recovery and an increase in direct energy requirements. However, cleaning programmes can be put under pressure in the pursuit of maintenance contract cost savings. Often there is little direct relationship between the budget holders for maintenance activities and the variable energy costs associated with that equipment. This is a key reason why energy performance review needs the correct managerial structure and authority to enable cross-department decisions to be made.

Examples include:

• Feed/Efﬂuent exchangers in furnace preheat trains

• Boiler and Furnace ﬂue gas recovery systems (convection banks, waste-heat boilers, air-preheaters)

• Furnace tube soot-build up and fouling (especially with heavy liquid fuels and incinerated waste products)

• Dust build-up on overhead ﬁnfans (can impact downstream refrigerant systems or compression systems)

• Fouling of tempered and cooling water systems. (ditto)

• Fouling of turbine blades

• Cooling Tower Performance

Cleaning methods are obviously many in nature and some focus on a particular application. However the (relatively slow) nature of the fouling process lends itself to online condition monitoring which in combination with process cost models allows evaluation and prediction of the optimum (cost effective) cleaning point. This is covered in 10.4.5.

10.4.2 Steam Leak Programmes

Clearly for plants with high pour-point materials steam tracing is a necessary fact of life. And that inevitably means steam leaks. However a focussed approach to steam leak repairs can bring signiﬁcant steam savings as well as consequential beneﬁts in terms of safety (no ﬂumes), housekeeping and general pride in operations.

In less than 6 months a large UK petrochems site saved

£1.2Mpa in steam leaks from a 4-man steam team.

(1 engineer, 1 foreman, 2 welders). After an initial site

survey, the engineer would prioritise and select a list of

leaks to be ﬁxed each week. The Site was behind the initiative, permits to work were efﬁciently handled and the results well publicised. The effect was a transformation in

both site attitudes, visual impact and ﬁnancial beneﬁt.

‘Steam Team’ example

The following steps are recommended for saving energy in the steam condensate distribution system and starting an effective steam energy management programme:

• Appoint a steam leak custodian with express responsibility for running the programme

• Develop a standardised leak estimation methodology that you wish to use. There are many in open literature as well as from the major steam trap manufacturers. Different degrees of complexity are available and different methodologies (e.g. plume size estimation vs. oriﬁce-based). The important thing is to adopt a site standard which suits and use it consistently

• Agree a steam value pricing structure. Apart from prioritising work it is a valuable element of any awareness campaign

• Run a survey, recording all leaks, size, cost, and location

• Allocate a budget and (ideally) a dedicated ‘steam-team’ charged with methodically working through the prioritised leak-ﬁxing list

• Publicise success – the weekly results

Common Energy Tools and Techniques

10.4.3 Steam Trap Monitoring

Along with the steam leak activities a pro-active and organised approach to maintaining steam traps is required. A large petrochemical site may have tens of thousands of steam traps. Clearly a full checking programme is unfeasible however the large population does allow a risk-based inspection approach. Modern wireless-based failure monitors allow monitoring of key applications.

Effect of Inspection on Steam Trap Failure Costs

0 1 2 3 4 5

Inspection interval (years)

Inspection cost Steam losses Repair costs Total costs

Cost per year (¤/yr)

700

600

500

400

300

Thousands

200

100

Key factors needed to be taken into account when designing an inspection programme are:

• Cost of vented steam during failure

• Cost of inspection programme

• Average repair cost per trap

• Inspection rate/yr

• Average failure rate (%fail/yr)

• Average delay between failure and inspection (months)

• Population

Case Number

Estimated Heat Loss from a 600 F, 8-inch NPS Pipe

Common Energy Tools and Techniques

From this it is a relatively straightforward analysis to determine the most cost-effective inspection programme, balancing inspection costs vs. lost steam costs. It also allows an understanding of the effect of failure rate can inﬂuence the outcome, investigating the effect of trap upgrades etc.

There are a variety of inspection techniques – ultrasonic, pyrometer, handcheck and the reader is steered towards manufacturer and service provider literature in making his assessment.

An attractive new tool on the steam trap market is the wireless monitor. Typically a simple battery operated strap-on device it uses acoustic technology to monitor steam trap performance. Two roles can be envisaged: monitoring of key high capacity traps (e.g. on MPS systems) and secondly for gathering statistical failure data which will allow a higher quality inspection programme to be constructed.

10.4.4 Lagging

Often ignored, the effects of lagging degradation can be signiﬁcant.

The Netherlands Centre for Technical Insulation has calculated the effect of damaged or missing lagging on productivity and the environment. Estimates are that 5 to 10 percent of oil reﬁnery systems are badly insulated or not insulated at all in the European Union; for the United States, estimates are 20 to 25 percent. One reﬁnery with a capacity of 300,000 bbl/day was examined and found to be losing 4,500 bbl/day due to insufﬁcient insulation – a loss of roughly $200 million per year. Reducing the reﬁnery’s losses with proper

insulation would cost approximately $25 million, with a payback of two

7,000

6,500

6,000

5,500

5,000

4,500

4,000

3,500

3,000

2,500

2,000

Heat Loss, Btu/hr-LF

1,500

1,000

500

Uninsulated Pipe

Pipe Insulated with

1.5" MF Pipe Insulation

1 2 3

Pipe with Damaged

or Missing Insulation

months. This would save 500,000 t/a of CO

emissions.

All too often, routine maintenance involves removal and replacement of insulated items. However, insulation removed by plant personnel or by other contractors’ personnel is usually not replaced unless speciﬁcally noticed. At Turnarounds, replacement of insulation can get left over as the ﬁnal job on the Turnaround.

Pipe Temperature, Degrees F

200 300 400 500 600 700 800 900 1000

Heat Loss from an Uninsulated 8-inch NPS Pipe

Common Energy Tools and Techniques

Rain and corrosion plus minor damage can quickly lead to a loss in insulation performance.

Thus a regular programme of lagging and insulation inspection is a very important element in any energy conservation programme. Loss calculation methods are widely available. Infra-red scanning is a common technique. In some cases monitoring of

18,000

16,000

14,000

12,000

10,000

8,000

6,000

4,000

Heat Loss, Btu/hr-LF

2,000

rundown temperatures can indicate potential performance loss of a period of time.

10.4.5 Use of Asset Monitoring Techniques

Equipment monitoring software, typically linked to a DCS/Process Historian, has become widely available during the last decade. Model-building and coding techniques are now within the grasp of engineers without the need for specialist maths and programming skills. Modern computing power enables quick computation and convergence of the ﬁtting and optimisation routines that are core to the software. Different approaches are possible:

• Rigorous ﬁrst principles modelling

• Straight statistical modelling

• ‘Grey-box’ modelling which combines known and scientiﬁc-based understanding of physical processes with statistical modelling –thus better able to handle measurement error, modelling inaccuracy and un-modelled effects.

Whilst initially aimed at fault detection these techniques can be a very useful tool in an energy-based maintenance strategy. Energy performance degradation is typically a slower process driven by factors such as fouling and as such is a good candidate for long term monitoring.

Typically a model will be ﬁtted to (real-time) plant data (e.g. using hourly average data to take out short term noise). The calculated ﬁtting parameter(s) will be an engineering quantity which has a direct relation to the energy performance issue – e.g. a heat transfer coefﬁcient, boiler efﬁciency, turbine efﬁciency. The ﬁtted model can be used in two ways:

1. Alarming of current condition. This could be combined with some form of SPC (Statistical Process Control) monitoring.

2. The development of time-based models for the calculated model parameters which can then be used as predictive models to investigate future operational and maintenance options. As the model is updated it becomes an up to-date representation of the latest situation and is the best knowledge for future planning. Typically this can be combined with maintenance planning systems to determine cost-effective optimum cleaning and intervention points.

Common Energy Tools and Techniques

Common applications include:

• Heat Exchanger fouling and performance prediction

• Turbine efﬁciency monitoring

• Boiler and Furnace efﬁciency monitoring

• Gas turbine performance

• Pump Curve – operation with respect to best efﬁciency point

• Cooling Tower efﬁciency

Ideally the modelling package should use the same common data as the EMIS and its results should be fed back for data storage and reporting within the EMIS.

To get best results the use of such packages needs formalising – results presented and decisions made on a regular basis laid down by the EMS maintenance processes rather than as an occasional technology hobby used by one engineer.

10.5 Pinch Analysis and Improved Heat Recovery

The techniques discussed so far have generally been supportive methodologies to improve the operational energy efﬁciency of a unit. The basic plant has remained the same. Major Capital Projects have not been discussed.

However operations do change. Different feedstock, product requirements and so forth gradually change the operating conditions. Equipment is likely to run at different temperatures and ﬂows from the original design. Controllability and contingency factors from the original design cases are likely to have been superseded. And these considerations particularly apply to the process heat integration or heat recovery systems employed. Indeed on an older unit there may be very poor heat integration with excessive energy wastage (a quick check on product rundown temperatures is a useful indication – how do they compare to storage requirements? – is too much heat being sent to cooling water?)

This leads to the consideration of a more fundamental revisit of the unit heat integration and energy utilisation. In recent years the methods of Process Integration and more speciﬁcally Pinch Analysis have proven successful in addressing these issues.

10.5.1 Pinch Analysis

The technique of Pinch Analysis were ﬁrst developed in 1977 by Bodo Linnhoff under the supervision of Dr John Flower at the University of Leeds and since then has emerged as one of the most practical tools in the ﬁeld of process integration, particularly for improving the efﬁcient use of energy, water and hydrogen. It is well used in the Chemicals, Petrochemicals, Oil Reﬁning, Pulp & Paper, Food & Drink and Steel/Metallurgy sectors.

Common Energy Tools and Techniques

Process Stream Data

Pinch Analysis provides tools that allow the investigation of energy ﬂows within a process and to identify the most economical ways of maximising heat recovery and minimising demand for external utilities. Whilst it obviously has a place in new designs, in retroﬁt projects pinch analysis can be speciﬁcally aimed at maximising the return on project investment and allows evaluation of combinations of project ideas.

An important element to pinch analysis is the establishment of minimum energy consumption targets for a given process or plant. This information enables the identiﬁcation of the maximum potential for improvement before beginning the detailed process design.

The use of specialised software is generally required. Some software applications offer tools to rapidly design heat exchanger networks. A model of the Site’s utility systems is generally produced as part of the pinch study. This enables process energy savings to be directly related to savings of primary energy purchases.

Typical reported savings across the sectors identiﬁed above have been in the region 10 to 35%

(Source: Pinch Analysis for the Efﬁcient Use of Energy etc. Natural

Heat Sources

Resources Canada).

One of the principal tools of Pinch Analysis is the graphic representation of composite curves. The process data is represented as a set of energy ﬂows, or streams, as a function of heat load (kW) against temperature (deg C). These data are

Composite Curves

combined for all the streams in the plant to give composite curves, one for all hot streams (releasing heat) and one for all cold streams (requiring heat). The point of closest approach between the hot and cold composite curves is the pinch point with a hot stream pinch temperature and a cold stream pinch temperature. This is where the design is most constrained.

Energy Recuperation Potential

Hot Composite Curve

Pinch Point

Cold Composite Curve

Hence, by ﬁnding this point and starting the design there, the energy targets can be achieved, recovering heat between hot and cold streams in two separate systems, one for temperatures above pinch temperatures and one for temperatures below pinch temperatures. In practice, during the pinch analysis of an existing design, often cross-pinch exchanges of heat are found between a hot stream with its temperature above the pinch and a cold stream below the pinch. Removal of those exchangers by alternative matching ensures the process reaches its energy target.

The detailed exploitation of Pinch Analysis, whether for heat exchanger networks, utility system design or cogeneration applications, is beyond the scope of this text. Indeed specialist skills and software are needed. However it can play an important part in reassessing and optimising the energy and utility proﬁles across a unit. Suggested further reading is included in Appendix H.

Common Energy Tools and Techniques

10.6 Variable Speed Drives

Variable speed drives (VSDs) can lead to signiﬁcant energy savings associated with better process control, less wear in the mechanical equipment and less acoustical noise. When loads vary, VSDs can reduce electrical energy consumption particularly in centrifugal pumps, compressors and fan applications – even up to 50%. Materials processing applications like centrifugal machines, mills and machine tools, as well as materials handling application such as winders, conveyors and elevators, can also beneﬁt both in terms of energy consumption and overall performance through the use of VSDs.

The use of VSDs can provide other beneﬁts including:

• extending the useful operating range of the driven equipment

• isolating motors from the line, which can reduce motor stress and inefﬁciency

• accurately synchronising multiple motors

• improving the speed and reliability of response to changing operating conditions

Whilst VSD technology has been around for many years the costs tended to limit its application to high power applications. However, modern inverter electronics have reduced typical capital costs signiﬁcantly and the technology is now much more suited to smaller applications.

Case study – A refrigerant system with a small 10KW compressor which operated under a variable load proﬁle during the day achieved power savings of 40% by the installation of VSD. Simple payback time was

2.4 years despite operation being limited to the period May to October each year.

Note: VSDs are not applicable for all applications, in particular where the load is constant (e.g. ﬂuid bed air input fans, oxidation air compressors, etc.), as the VSD will lose 3 – 4% of the energy input (rectifying and adjusting the current phase).

Skills and Competencies for Energy Activities

11 Skills and Competencies for Energy Activities

In describing the setting up of an Energy Improvement Programme the subject of roles and skills was brieﬂy mentioned (Section 4.3). The forthcoming Chapter looks in more detail at the competencies and skill levels required both for energy improvement programmes and the development of EMS. Given the broad range of energy factors a correspondingly wide range of disciplines is involved and striking the balance between full time and specialist resource is a ﬁne line.

11.1 Organisational Core Competencies and Skill Areas

These skills are needed for everyday energy-related activities and should generally be available as part of the local-on-site resource. In most cases these are energy competencies being part of a broader job.

11.1.1 Site Energy Manager

This is (ideally) a dedicated position. The incumbent would typically be an experienced engineer with a strong operational overview and experience from across the site. This is NOT a ﬁnancial or book-keeping position. Key competencies and knowledge areas:

• Operations and Process Engineering

• Business Planning and Scheduling

• Understanding of site organisation and decision-making processes

• Benchmarking and data-analysis techniques

• Economics and product/utilities valuation

• Ability to track/exploit External trends and developments (technical and business)

• Facilitation/Communication skills

• Understanding/Appreciation of energy efﬁciency technologies

11.1.2 Process Engineers

All process engineers providing day-to-day operations support should have basic energy efﬁciency competencies:

• Thorough understanding of how process operation and operating conditions affect energy consumption on their unit

• Thorough understanding of how Site fuel and utility systems impact their unit

• Standard Chemical Engineering skills – heat and mass balances, heat transfer, thermodynamics, separation processes, modelling etc

• Basic equipment operational and modelling knowledge – furnaces, turbines, heat exchangers, steam traps

• Appreciation of modern control and instrumentation techniques

• Appreciation/understanding of advanced modelling techniques (Pinch analysis, Steam simulations etc)

• Process Historian report building and data analysis skills

• Process economics

Skills and Competencies for Energy Activities

11.1.3 Utilities Engineering

Very much dependent on installed utilities infrastructure but key skills likely to include (in addition to basic process engineering skills):

• Detailed Boiler operation and performance assessment

• Power distribution - operational aspects

• Steam systems and networks - balancing and optimisation

• Turbine performance and troubleshooting

• Water Treatment Chemistry

11.1.4 Control and Instrumentation

The ability to measure and control energy-related streams is an absolutely essential requisite for efﬁcient operation. On-site capabilities should include:

• Instrumentation design (simple loops), diagnostic, servicing skills

• DCS/Process Historian conﬁguration skills (tags, calculations, displays, reports)

• Process control Loop Tuning

• Basic Control design and conﬁguration

• Advanced Control – ﬁrst line support

11.1.5 Operational Staff

The distribution of skills will depend on role-allocation within the operational (shift) teams – for instance the use of dedicated furnace operators as opposed to a fully multi-tasking rotating pattern.

• All operators should understand the basic operational drivers on their units energy efﬁciency (e.g. stack oxygen, equipment performance, recycle rates, stripping steam, impact of reﬂux and reboil etc) and how they can be inﬂuenced from the panel and in the ﬁeld

• All operators should understand the basic energy efﬁcient equipment procedures – for instance how and when to operate sootblowers, check steam-trap operation, deaerator operation, drain condensate, report steam leaks, pump drive selection and so forth

• Panel operators need a sound understanding of how the process control loops affect energy consumption – heat integration, furnace controls, fuel selection, stability concepts, constraint pushing, distillation conditions

• Furnace skills (if appropriate) – ﬂame pattern interpretation, air register manipulation, burner cleaning, burner procedures (changing tips and plugs)

11.2 Important Specialist Support Skills

The Site will need access to reliable and in-depth specialist engineers to compliment the day-to-day operation. This may be sourced from a variety of places: corporate technical centre, individual specialist consultancies, integrated engineering consultancies, EPC contractors and equipment suppliers. Adoption of an integrated approach which enables a complimentary set of experts who work together and are aware and understand the limits and boundaries of their areas of expertise, is good practice.

Typical of the specialist skills that a processes site may commonly require:

Combustion design and operation. Covering both furnace design as well as burner operation (setting minimum stops, ﬂame impingent, fuel supply design and operation).

Skills and Competencies for Energy Activities

Heat transfer. For issues such as heat exchanger design and unit conﬁguration, (Pinch Analysis), fouling assessment and abatement.

Power generation. Turbo-alternator design and operation, generators, drives.

Turbines and rotating equipment. Compressor operation, anti-surge control, drive changes.

Compressed Air. Utilisation of waste compressor heat, minimisation of leaks, ﬁlter monitoring, and

optimisation of system pressures.

Advanced control and optimisation. Advanced Model Predictive Control, real-time utilities, process modelling and optimisation techniques.

Measurement. Particularly for selection and design of difﬁcult measurement situations – ﬂow measurement techniques, on-line analyser selection, sampling systems.

Process and Statistical modelling. Developing energy base-line models, investigating non-obvious driver mechanisms, benchmarking analysis, KPI-Driver correlations.

11.3 EMS and EMIS skills and competencies

EM(I)S development and implementation requires a full cross section of skills. These will vary depending on the phase of the project. Fundamentally it is a change management project although there is a need for a strong operational and process engineering input plus some supporting skills in Process IT. Clearly underpinning the technical skill areas is a strong element of communicational and project management skills. Fundamentally EMIS is addressing the day-to-day management processes for a Manufacturing Site. New ways of working will be needed, existing processes may be challenged. Often energy drivers are at odds with existing yield or production strategies. Hence the ability to engage the site and staff to take the debate forward and resolve the issues in a positive manner is essential.

Skills needed within a team responsible for developing EMS and its associated information system:

Unit Operations/Business Knowledge. Understanding of process conﬁguration, ﬂowschemes and unit operations plus the appropriate supporting managerial and technical processes, organisational structures, business drives, operational practices and cultures.

Business Economics. Basic business economics, planning, scheduling and marginal pricing philosophies, project economics.

Process Engineering. Process engineering essentials, heat and mass transfer, thermodynamics, standard design and calculation methodologies. Process modelling and Flowsheeter capability.

Datamining. Ability to use statistical and mathematical modelling tools and techniques, particularly in the analysis of time-series process data.

Skills and Competencies for Energy Activities

Process IT and Instrumentation Architecture. Understanding of typical Process IT, Instrumentation systems and architecture. DCS and process computing and relation to business computing structures. Typical applications architecture (what service, where executed), relationship with Business/Ofﬁce computing, basic components, functionalities and vendors.

Process IT Coding. Hands on programming and conﬁgurations skills for modern Process Computing systems: graphics building, report generation, calculations coding and programming.

TQM. Understanding of Management Systems, ISO 9001 etc.

Change Management. Knowledge of change management techniques, introduction of new approaches to

working, team building, motivation, training etc.

Clearly it is expected that an individual person will be able to handle several of the competency requirements for any given EMIS activity. The purpose if the matrix is to assist managers in building a team and also provide a check-list to anyone undertaking an EMS activity that they have the appropriate knowledge and skills to undertake the job.

11.4 Skill Management

Most companies these days employ some form of training and skills management system, often as part of the HR system. These allow the recording and assessment of both skill requirements for a particular position and also the abilities of the individual engineer. Thus individual training and competency plans can be developed and progress tracked.

It is important that Energy-related competencies are included in this - in particular if a registration to ISO 50001 is being considered. It is also useful to consider depth of expertise on an area. Complex categorisation systems are available however a simple two-level approach is quite feasible where a skill level is simply assessed as ‘Aware’ or ‘Professional’.

Awareness

A good knowledge of what is involved in that Area of Expertise and its relevance to the business

• Understanding the main elements of the Area of Expertise and their importance to the business

• Understanding how and where competences in the Area of Expertise are relevant to the task

Professional

Being able to carry out consistently the activities of an Area of Expertise to the required standard.

• Able to perform satisfactorily majority of activities of the Area of Expertise

• Able to translate guidelines and standards for the Area of Expertise into practical actions

• Able to solve imaginatively common technical/operational problems in the Area of Expertise

• Able to guide and advise others in operational/technical aspects of the Area of Expertise

The EU Energy Efficiency Directive

12 The EU Energy Efﬁciency Directive

12.1 History and Development

Energy efﬁciency is not only about improving supply security and reducing energy cost. It is also an integral part of a long term vision of moving towards a resource efﬁcient and low-carbon economy. Using energy more efﬁciently will lead to a reduction of the overall greenhouse gas emissions generated, thereby supporting policies against climate change. In addition, energy efﬁciency has the potential to be a major stimulator for economic recovery and growth. The EU industry will become more competitive by reducing its own energy consumption and, at the same time, the energy efﬁciency service sector provides a new green growth market and job creator.

In that respect, energy efﬁciency is a fundamental part of broader initiatives of achieving the EU’s energy, climate change and industrial policy objectives and largely contributes to the EUROPE 2020 Strategy.

The European Council in March 2007 set three ambitious objectives to be reached by 2020 as part of the EU integrated climate and energy policy framework, save 20% of the EU’s total primary energy consumption, and binding objectives to increase the share of renewable energy of the EU ﬁnal energy consumption by 20% and to reduce the EU greenhouse gas emissions by 20% compared to 1990 levels. In addition, the EU Council endorsed an agreement that at least 80% of GHG emissions reduction is needed by 2050.

None of these objectives can be reached without streamlining and strengthening the EU and existing national frameworks for energy efﬁciency. The newly adopted Energy Efﬁciency Directive is an important step towards a more stringent and harmonised EU energy policy that puts energy efﬁciency at the centre, setting the path for action in this ﬁeld up to 2020.

It is a more coherent and comprehensive framework that, if correctly implemented, will help to exploit the EU cost-effective energy saving potentials in both the supply (generation, transmission, distribution) and the demand side.

12.2 Highlights

The EED provides a stronger legislative framework to drive Industry towards greater energy efﬁciency. Whilst the EED covers a complete spectrum of activities, from domestic energy usage through buildings, transport, distribution and Industry, the key issues relevant to the Process Industry sector are the encouragement to implement energy management systems and also the requirement for large industrial plants to undergo regular energy performance audits by externally accredited auditors. The EED speciﬁcally mandates Member States to encourage SMEs to adopt Best Practice in these areas.

Minimum requirements are speciﬁed in the EED to form the basis for Member States to develop their legislation and local standards.

Speciﬁc Energy Consumption targets are realised through Energy Obligation schemes which require energy retailers and distributors to achieve cumulative energy savings of 1.5% annually amongst their endusers between 2014 and 2020. There is limited exemption (max 25% of total country savings) for industries

The EU Energy Efficiency Directive

subject to the Emissions Trading Scheme and Member States are allowed to bring in their own policy measures in support of achieving energy savings amongst ﬁnal customers. Measurement and veriﬁcation of energy savings is a key requirement of the EED.

In terms of managing supply and distribution systems, National Energy Regulators are required to encourage demand response systems in order to better manage customer consumption of electricity according to supply conditions. For example, having electricity customers reduce their consumption at critical times or in response to market prices. Clearly this can impact the process industry in terms of its internal site load management and indeed offer opportunities for active participation with distribution companies.

It has been demonstrated that district heating schemes are one of the most attractive ways of improving the energy efﬁciency of large process industries. Particularly in the recovery of “low level” heat (e.g. <80 °C) which is otherwise lost to cooling water or atmosphere. Major steps in energy efﬁciency are achievable although at an obvious high capital cost and involving complex inter-company/government infrastructures. In the Oil Industry the reﬁneries (predominantly Scandinavian) which have adopted this technology stand clear of their peers at the top of energy efﬁciency benchmarking and comparison. The EED requires Member States to carry out a ‘comprehensive assessment’, by December 2015, that identiﬁes cost-efﬁcient ways to further develop the necessary infrastructure and to accommodate the development of high-efﬁciency Combined Heat and Power (CHP) as well as the use of heating and cooling from waste heat and renewable energy sources. This has the potential to be a major efﬁciency factor for the Process Industry.

Supporting these speciﬁc issues are a series of so-called ‘horizontal’ provisions which cross all sectors such as promotion of the energy services market, availability of certiﬁcation schemes to promote technical competence, removal of barriers to energy efﬁciency, freedom of information etc.

12.3 Main recommendations for the Process Industries

The EED is a comprehensive document which ultimately serves many sectors. It is also directed at the Member States who are required to develop national legislation to bring the EED requirements into local law. Many requirements are directed at the detailed management of the EED by the Member States. However what follows are the highlights of the main impacts on the end user process industries.

12.3.1 Energy Audits

For the process industries the key impact will be the requirement to undergo regular energy auditing. In this case an ‘Energy Audit’ means “a systematic procedure with the purpose of obtaining adequate knowledge

of the existing energy consumption proﬁle of an industrial or commercial operation or installation, identifying and quantifying cost-effective energy saving opportunities, and reporting the ﬁndings”. This is supported by

national systems of accreditation and certiﬁcation of external auditors to carry out the audits.

Full requirements are given in Article 8 of the EED. These will be established in national legislation by each Member State, and may indeed be enhanced or made more stringent. Key aspects that have direct impact on process industry companies are summarised as follows.

12.3.1.1 Requirements to undergo auditing

It will be mandatory for all large companies which are not classiﬁed as SMEs to undergo energy audits within 3 years of the EED coming into force and then at least once every 4 years afterwards.

The EU Energy Efficiency Directive

The audits must follow the minimum standards (set out in 12.3.1.4 below) and carried out in an independent manner and subject to quality assurance. – i.e. carried out by qualiﬁed and/or accredited experts or implemented and supervised by independent authorities under national legislation.

Note on ‘in-house’ auditors. The EED does not speciﬁcally exclude auditing by in-house staff provided they are trained and certiﬁed by the independent authorities as outlined above. They will be subject to random annual checking for quality compliance by the independent authority. The EU Working Group on this article has also stated that ‘where audits are carried out by in-house experts the necessary independence would require these experts not to be directly engaged in the activity being audited’. Thus would seem to preclude local staff from carrying out the audit on their own location although corporate/ head ofﬁce experts or staff from another site could do so.

12.3.1.2 Auditing and Energy Management Systems Exemption

Exemption from the obligation to carry out regular energy audits can be granted to companies who have adopted an energy or environmental management system (e.g. ISO 50001 or ISO 14001) provided:

• That the management system is certiﬁed by an independent body according to the relevant European and International standards.

• That the management system speciﬁcally includes energy audit requirements in line with the EED (12.3.1.4 below).

12.3.1.3 Requirements on SMEs

• There are no hard and fast requirements on SMEs but there is a requirement on Member States to support and encourage SMEs to adopt energy efﬁciency best practice:

• SMEs will be encouraged to undergo energy audits and the subsequent implementation of the audit recommendations

• Member States must bring to the attention of SMEs concrete examples of how energy management systems can help their business

• To assist SMEs, Member States should adopt a favourable framework aimed at providing technical assistance and knowhow

12.3.1.4 Minimum Audit Standards

• Minimum criteria for energy audits including those carried out as part of energy management systems. The energy audits referred to in the EED Article 8 shall be based on the following guidelines:

• Be based on up-to-date, measured, traceable operational data on energy consumption and (for electricity) load proﬁles

• Comprise a detailed review of the energy consumption proﬁle of.... buildings industrial operations or

installations, including transportation

• Build, whenever possible, on life-cycle cost analysis (LCCA) instead of Simple Payback Periods (SPP) in order to take account of long-term savings, residual values of long-term investments and discount rates

• Be proportionate, and sufﬁciently representative to permit the drawing of a reliable picture of overall energy performance and the reliable identiﬁcation of the most signiﬁcant opportunities for improvement

• Energy audits shall allow detailed and validated calculations for the proposed measures so as to provide clear information on potential savings

• The data used in energy audits shall be storable for historical analysis and tracking performance

The EU Energy Efficiency Directive

12.3.2 Energy Targets and Obligation Schemes

Member States are required to introduce Energy Obligation Schemes (or alternate policy measures – see

12.3.2.2) as a means of achieving cumulative end-use energy savings by 31st December 2020 equivalent to

1.5% annual savings from 2014 to 2020.

However there are several options as to how Member States both calculate the target and develop their national policies. Inclusions and exclusions are many and allow Member State ﬂexibility.

12.3.2.1 Requirements on Member States

Each Member State will go though a process to develop either an energy efﬁciency obligation scheme or alternative policy measures designed to achieve energy savings amongst end users. In particular they are required to:

• Establish the total quantity of energy savings that has to be achieved and its spread over the obligation period

• Establish which sectors and individual actions are to be targeted so that the required amount of energy savings is achieved

• Decide whether to use energy efﬁciency obligation schemes or alternative policy measures, and, while designing the schemes or measures, ensure that certain criteria are met

• Establish how energy savings from individual actions are to be calculated

• Ensure control, veriﬁcation, monitoring and transparency of the scheme or alternative policy measures

• Report and publish the results

12.3.2.2 Sectors to be included/excluded

To quote the EED article 7.

“The savings target shall be at least equivalent to achieving new savings each year from 1 January

2014 to 31 December 2020 of 1,5% of the annual energy sales to ﬁnal customers of all energy

distributors or all retail energy sales companies by volume, averaged over the most recent three-year

period prior to 1 January 2013. The sales of energy, by volume, used in transport may be partially or

fully excluded from this calculation…’’

In calculating the total energy savings and hence obligations targets other speciﬁc exclusions include the industries listed as being subject to the Emissions Trading Scheme (EU Directive 2003/87/EC). However this exclusion is limited to a maximum of 25% of the total country savings.

The Directive prescribes that all ﬁnal energy (with the possible exception of energy used in the transport sector) that is purchased by a natural or legal person is included in the calculations. Energy volumes transformed onsite and used for own-use, and those that are used for production of other energy forms for non-energy use are to be excluded. This implies that processes that burn their own by-products, liquids and gases for internal consumption would be excluded.

Thus the extent of the obligation calculations and the impact of targets on individual end users in the process industries is very much for local implementation.

12.3.2.3 Alternate Policy Measures

As an alternative to setting up an energy efﬁciency obligation scheme, Member States may opt to take

The EU Energy Efficiency Directive

other policy measures to achieve energy savings among ﬁnal customers. The annual amount of new energy savings achieved through this approach shall be equivalent to the amount of new energy savings required by paragraphs the Obligation scheme calculations. Provided that equivalence is maintained, Member States may combine obligation schemes with alternative policy measures, including national energy efﬁciency programmes.

The policy measures may include, but are not restricted to: (a) Energy or CO

taxes that have the effect of reducing end-use energy consumption.

(b) Financing schemes and instruments or ﬁscal incentives that lead to the application of energy-efﬁcient

technology or techniques and have the effect of reducing end-use energy consumption.

techniques and have the effect of reducing end-use energy consumption. (d) Standards and norms that aim at improving the energy efﬁciency of products and services. (e) Energy labelling schemes, with the exception of those that are mandatory and applicable in the Member

States under EU law. (f) Training and education, including energy advisory programmes that lead to the application of energy-

efﬁcient technology or techniques and have the effect of reducing end-use energy consumption.

12.4 How will it be managed? How does the EED apply to you?

At the time of writing the Member States are in the process of developing their own local legislation on the basis of the EED. How this will develop and the extent that individual Member States impose more stringent requirements than the basic EED remains to be seen. For instance the Auditing requirements are described as minimum requirements and speciﬁc topics that may be included in audits are not listed – a Member State may add these. Also the mechanisms for running and administering the local audit processes have to be developed.

The key decision is whether to adopt a formally recognised Energy or Environmental Management System (ISO 50001/14001) as, correctly formulated, this will remove the need for external periodic energy audits by the Government appointed auditing function. Of course it must be recognised that developing and maintaining a registered ISO system takes time and resources so there is a balance to be struck. However for a Site/Company with a strong existing culture in ISO systems then this would appear a sensible route.

However the key preparation for all events is to develop at least the basic elements of an Energy Management Strategy and system i.e. following the basic building bricks of Chapter 4 onwards. The ﬂow chart in 4.1 illustrates the steps. This is indispensible best practice which will align a site’s energy efﬁciency practices so as to be best prepared for either external auditing or ISO registration. Should a Member State decide to adopt strict energy target setting of industries under the Obligations scheme the same discipline of energy management is essential if a company is to be able to respond to the rigours of energy target setting.

Benefits and Case Studies

13 Beneﬁts and Case Studies

Exact beneﬁt projections for energy efﬁciency activities are location speciﬁc and require detailed analysis of the pre-project situation. However there is a growing consensus and feedback of typical achieved beneﬁts from many sources.

Worldwide energy improvement programmes have been rolled out by multinational companies such as Exxon (GEMS programme ) and Shell (Energise programme) and at conferences they consistently report energy efﬁciency beneﬁts in the region of 5-10% of a Sites energy consumption with some individual sites running up to 20%.

The EU Best Available Techniques for Energy Efﬁciency Guide (read or download via

http://eippcb.jrc.es/reference/) provides a comprehensive list of typical beneﬁts attributable to various

energy efﬁciency techniques – furnaces, control, drives, compressed air, HVAC etc. – in particular sections

7.4, 7.5, 7.6 quote many case studies and examples. The individual sector guides (steal, paper, oil etc downloadable for the same site) provide useful benchmark data for typical process energy consumption.

Regional variations do occur, perhaps reﬂecting culture and history. US locations tend to report higher efﬁciency gains than European locations, probably reﬂecting the greater impact of the 1970s Oil Crises in Europe which kicked off energy efﬁciency issues earlier. Scandinavian locations often show up well in energy benchmarking due to the greater use of district heating and other heat recovery schemes which have been driven by their society and culture. Thus there is less scope for improvement as they are already well placed.

13.1 The Beneﬁts from Energy Management Systems

The beneﬁts of an EMS are more difﬁcult to directly quantify as of course they come from the results of individual energy saving activities. Double accounting should be avoided. The issues are sustainability and driving new improvement.

An important conference organised by the Texas Technology Showcase in Galveston, December 2006 brought together many major industrial users and consultancy/system suppliers. (Papers available through

http://texasiof.ces.utexas.edu/). Both users and suppliers consistently reported problems with beneﬁt

erosion in their energy programmes and there was universal agreement that Energy Management Systems were the key element in ensuring efﬁciency gains were maintained.

It is also clear that an active energy management culture will drive improvement and look for new energy saving opportunities both operationally, culturally and through capex. Some of these gains will be low cost some will require expenditure.

Ascribing a hard value and simple payback to an EMS/EMIS implementation is not easy. It is a point where life-cycle cost analysis comes in. In the project planning economics for an energy efﬁciency programme it may be appropriate to apply an erosion factor (say 50% over 5 years) for programmes which do not include EMS. Conversely, if an EMS is to be developed as part of the programme then the inclusion of additional annual future energy savings of perhaps 1-2% of site consumption to reﬂect the future impact of an EMS could be made.

Benefits and Case Studies

13.2 Case study 1 – Performance Modelling and Measurement

A US fossil-ﬁred power plant was experiencing large temperature swings under load change conditions. On-line modelling indicated problems with air ﬂow measurements. After the problems were corrected and instruments recalibrated it was possible to increase the ramp rate by 66% and reduce stack oxygen contents by one third.

This allowed the units to be turned down under automatic control and the minimum loads to be reduced by 40%. This resulted in beneﬁts of $1.4m per annum. In addition, performance monitoring of the air-preheater on 1 boiler indicated poor heat transfer and thus increased fuel use. Subsequent repairs to the air preheater resulted in fuel savings of $240,000 per annum.

13.3 Case Study 2 – the Role of Maintenance and Management

A large integrated oil/petrochemical site in Europe carried out a detailed energy performance review and project (along the lines as suggested in Chapter 9). A dedicated on-site team worked for a two year period assessing performance, identifying projects and then implementing them.

The Site was technically mature, experienced and generally a respected operator. It had a history of competence and strong technical stafﬁng.

The Project team identiﬁed around 25 relatively low-cost energy efﬁciency projects which saved the Company some 10% of the Site’s energy consumption. The total project costs were around one third of the annual energy beneﬁts – i.e. a simple payback of a few months.

However the interesting ﬁndings being few ‘new technology’ projects – this was a mature site which had a good history of keeping abreast of trends. The major part (75%) of the beneﬁts came from equipment maintenance issues:

• Steam leaks and traps

• Convection bank cleaning

• Repairing air-preheaters

• Repairing leaking heat exchangers

• Furnace burner alignment

• Balancing steam distribution

• Getting control back in operation

It was clear that a (laudable) corporate focus on cost saving – in particular ﬁxed cost maintenance contracts – had been at the expense of energy performance. There was no energy strategy, target setting or monitoring which meant that performance erosion had steadily taken place. There was no forum for debating the costs/beneﬁt of these activities.

The project team put corrective measures in place, instituted repairs and developed EMS procedures to ensure that the beneﬁts were maintained.

Emerson Guide: EU-Energy-Efficiency-Directive-User-Guide-2013 Manuals & Guides

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Introduction

1.1 Preface

1.2 Intended Audience

1.3 How to use the Guide

Definitions, Acronyms and Terminology

The concept of Industrial Energy Distribution:

Energy Efficiency Challenges in 2013

3.1 Background

3.2 Process Industry Potential

4 Developing the Way Forward

4.1 The Overall Programme

4.2 Assessment of Site Energy Maturity - the Initial Health Check

4.3 Energy Programme Skills and Resources

5 Core Operation – The Energy Management System

5.1 Developing an EMS

5.1.1 The EMS Design Workshop

5.1.1.1 Timing and organisation

5.1.1.2 Attendees

5.1.1.3 Agenda

5.1.1.4 Outcomes

5.1.2 Basic Components of EMS – ‘Essential Best Practice’

5.1.2.1 Policy and Strategy

5.1.2.2 Accountabilities

5.1.2.3 Organisation

5.1.2.4 Competencies

5.1.2.5 Work Processes

5.2 ISO 50001

5.2.1 Plan-Do-Check-Act

5.3 Links to Corporate Systems

5.4 Development Support and further Information

6 Energy Management Information Systems

6.1 Objectives

6.2 The Components of EMIS

6.2.2 Data Structures/KPI and Target Setting Philosophy

6.2.3 Energy Driver Variables

6.2.4 Use of Energy Loss Points

6.3 Operating with EMIS & User Interfaces

6.3.1 User Interfaces

6.4 Development of an EMIS

6.5 Core Activities - System Building

6.5.1 Allocate Areas of Operation

Feedstocks

Products

Classes of Energy

6.5.2 Energy balances

6.5.4 Preliminary list of KPIs

6.5.7 Setting Targets for KPIs and Drivers

6.5.7.1 Historical Best performance

6.5.7.2 Statistical Correlation

6.5.7.3 First Principles Model

6.5.8 Data Validation

6.6 EMIS Skills and Competencies

6.7 Key EMS Applications and Processes

7 Energy Target Setting and Performance Review

7.1 The Energy Target Setting Process

7.1.1 Site Energy Monitoring Targets and KPI Structure

7.1.2 Annual Target Setting

7.1.3 Monthly Target Setting

7.1.4 Weekly Operational Targets and the setting of Operating Instructions

7.1.5 Daily and Real-time activities

7.2 The Energy Performance Review Process

7.2.1 Daily Energy Performance Review

7.2.2 Weekly Energy Performance Review

7.2.3 Monthly Site Energy Performance Review

9.1 The Energy Walkthrough

9.2.1 Team and Preparation

9.2.2 Assessment Process and Operational Reviews

9.2.3 Project Generation and Validation

9.3 Ongoing Improvement – The Mature Operation

9.4 Financial Planning and Project Economics

9.4.1 Standard Project Economics Techniques

9.4.2 Utilities Marginal pricing

9.4.3 Investment Thresholds for Energy Projects

10 Common Energy Tools and Techniques

10.1 Measurement and Control of Energy Streams

10.1.1 Mass and Energy Balances