Energy Storage in Electric Power Grids

This book deals with the management and valuation of energy storage in electric power grids, highlighting the interest of storage systems in grid applications and developing management methodologies based on artificial intelligence tools. The authors highlight the importance of storing electrical energy, in the context of sustainable development, in "smart grids", and discuss multiple services that storing electrical energy can bring. Methodological tools are provided to build an energy management system storage following a generic approach. These tools are based on causal formalisms, artificial intelligence and explicit optimization techniques and are presented throughout the book in connection with concrete case studies.

FOREWORD xi

INTRODUCTION xiii

CHAPTER 1. ISSUES IN ELECTRICAL ENERGY STORAGE 1

1.1. Difficulties of storing electrical energy 1

1.2. Why store electrical energy? 3

1.3. Value enhancement of storage in electrical grids 6

1.4. Storage management 9

1.5. Bibliography 13

CHAPTER 2. RECENT DEVELOPMENTS IN ENERGY STORAGE 17

2.1. Introduction 17

2.2. Storage technologies 17

2.3. Characteristics of a storage system 19

2.3.1. Energy storage capacity 19

2.3.2. Maximum power and time constant 20

2.3.3. Energy losses and efficiency 20

2.3.4. Aging 21

2.3.5. Costs 21

2.3.6. Energy and specific power 22

2.3.7. Response time 23

2.3.8. Gray energy 24

2.3.9. State of energy 24

2.3.10. Other characteristics 25

2.4. Hydraulic storage 26

2.4.1. Principle of hydraulic storage 26

2.4.2. Exercise: Lac Noir station 27

2.5. Compressed-air storage 32

2.5.1. Principle of compressed-air storage 32

2.5.2. First- and second-generation compressed-air storage 33

2.5.3. Adiabatic compressed-air storage 34

2.5.4. Air storage 35

2.5.5. Hydropneumatic storage 36

2.6. Thermal storage 38

2.6.1. Sensitive-heat storage 38

2.6.2. Latent-heat storage 39

2.7. Chemical storage 40

2.7.1. Electrochemical storage 40

2.7.2. Hydrogen storage 45

2.8. Kinetic storage 47

2.9. Electrostatic storage 48

2.10. Electromagnetic storage 49

2.11. Compared performances of storage technologies 51

2.12. Bibliography 52

CHAPTER 3. APPLICATIONS AND VALUES OF ENERGY STORAGE IN POWER SYSTEMS  55

3.1. Introduction 55

3.2. Introduction to power systems and their operation 59

3.2.1. Generation plants 60

3.2.2. Electric grids 65

3.2.3. Demand 68

3.2.4. Some basics of the operation of power systems 69

3.3. Services that can be provided by storage 84

3.3.1. Introduction 84

3.3.2. Services required for connection to the transmission grid 85

3.3.3. Potential additional services provided to a transmission system operator 88

3.3.4. Potential services provided by storage to a distribution system operator 91

3.3.5. Services for a centralized generation owner 107

3.3.6. Services for a renewable decentralized producer 108

3.3.7. Services for consumers 118

3.3.8. Benefits from market activities 124

3.4. Example of the contribution of storage to the treatment of congestion events 127

3.4.1. Indicator of state of charge of grid 127

3.4.2. Evolution scenario for electric grid 128

3.4.3. Treatment of congestion events in Brittany 128

3.5. Example of contribution of storage to dynamic support of frequency control in an island grid 131

3.5.1. Context and potential interest of this service 131

3.5.2. What is under-frequency load shedding? 131

3.5.3. Technical specifications of dynamic support 132

3.5.4. Method used for detailed study of dynamic support 135

3.5.5. Stage 1: theoretical approach 135

3.5.6. Stage 2: dynamic simulations 141

3.5.7. Stage 3: experimental laboratory implementation 142

3.5.8. Economic value making 144

3.5.9. Conclusion 145

3.6. General conclusion 145

3.7. Bibliography 146

CHAPTER 4. INTRODUCTION TO FUZZY LOGIC AND APPLICATION TO THE MANAGEMENT OF KINETIC ENERGY STORAGE IN A HYBRID WIND-DIESEL SYSTEM 153

4.1. Introduction 153

4.2. Introduction to fuzzy logic 154

4.2.1. Principle of fuzzy reasoning 154

4.2.2. Fuzzy logic and Boolean logic 155

4.2.3. Stages of a fuzzy supervisor 160

4.2.4. Example of fuzzy reasoning 164

4.3. Wind-kinetic energy storage combination on an isolated site with a diesel generator 168

4.3.1. Introduction 168

4.3.2. Energy management strategy 170

4.3.3. Fuzzy logic supervisor 171

4.3.4. Results of simulation with fuzzy supervisor 174

4.3.5. Results of simulation with simple filtering 176

4.4. Conclusion 179

4.5. Bibliography 179

CHAPTER 5. SUPERVISOR CONSTRUCTION METHODOLOGY FOR A WINDPOWER SOURCE COMBINED WITH STORAGE 181

5.1. Introduction 181

5.2. Energetic system studied 182

5.3. Supervisor development methodology 183

5.4. Specifications 184

5.4.1. Objectives 184

5.4.2. Limitations 184

5.4.3. Means of action 185

5.5. Supervisor structure 186

5.5.1. Input values 186

5.5.2. Output values 187

5.5.3. Supervisor development tools 187

5.6. Identification of various operating states: functional graph 191

5.6.1. Graph of level N1 192

5.6.2. Graph of level N1.1 193

5.6.3. Graph of level N1.2 194

5.6.4. Graph of level N1.3 194

5.7. Membership functions 195

5.8. Operational graph 199

5.8.1. Graph of level N1 200

5.8.2. Graph of level N1.1 200

5.8.3. Graph of level N1.2 201

5.8.4. Graph of level N1.3 201

5.9. Fuzzy rules 202

5.10. Experimental validation 203

5.10.1. Implantation of supervisor 203

5.10.2. Experimental configuration 204

5.10.3. Results and analyses 207

5.11. Conclusion 212

5.12. Bibliography 212

CHAPTER 6. DESIGN OF A HYBRID MULTISOURCE/MULTISTORAGE SUPERVISOR 215

6.1. Introduction 215

6.2. Methodology for the construction of a supervisor for a hybrid source incorporating windpower 217

6.2.1. Determination of system specifications 218

6.2.2. Structure of supervisor 220

6.2.3. Determination of functional graphs 223

6.2.4. Determination of membership functions 227

6.2.5. Determination of operational graphs 231

6.2.6. Extraction of fuzzy laws 233

6.3. Compared performance of different variants of hybrid source 234

6.3.1. Characteristics of simulated system 234

6.3.2. Simulations of different hybrid source variants 237

6.3.3. Comparison of performance of different hybrid sources by means of indicators 248

6.4. Conclusion 249

6.5. Appendices 249

6.5.1. Range of output value variations 249

6.5.2. Fuzzy rules 251

6.6. Bibliography 253

CHAPTER 7. MANAGEMENT AND ECONOMIC ENHANCEMENT OF ADIABATIC COMPRESSED-AIR ENERGY STORAGE INCORPORATED INTO A POWER GRID 255

7.1. Introduction 255

7.2. Services provided by storage 257

7.2.1. Storage planning 257

7.2.2. Frequency control 257

7.2.3. Congestion management 258

7.2.4. Guarantee of variable renewable production 258

7.3. Supervision strategy 259

7.3.1. Methodology 259

7.3.2. Objectives, constraints and means of actions 260

7.3.3. Supervisor structure 260

7.3.4. Determination of functional graphs 262

7.3.5. Determination of membership functions 267

7.3.6. Determination of operational graphs 270

7.3.7. Extraction of fuzzy rules 270

7.3.8. Indicators 270

7.4. Economic value of services 271

7.4.1. Purchase/sale action 272

7.4.2. Frequency control billing 273

7.4.3. Billing of additional services 273

7.5. Application 274

7.5.1. Test grid 274

7.5.2. Interest of the contribution of storage to ancillary services 275

7.5.3. Interest of fuzzy supervisor compared to a Boolean supervisor 279

7.6. Conclusion 281

7.7. Acknowledgments 282

7.8. Bibliography 282

INDEX 285

Benoit ROBYNS, Hautes Etudes d'Ingénieur, Lille, France

Bruno FRANCOIS, Ecole Centrale de Lille, France

Gauthier DELILLE, EDF, France

Christophe SAUDEMONT, Hautes Etudes d'Ingénieur, Lille, France