Grid Integration of Electric Vehicles in Open Electricity Markets

Professor Qiuwei Wu, Centre for Electric Technology, Department of Electrical Engineering, Technical University of Denmark, Lyngby Qiuwei Wu is an assistant professor with the Centre for Electric Technology (CET), Technical University of Denmark (DTU) and is currently involved in the research of integration of electric vehicles (EVs), integration of wind power, market driven optimal operation of distribution systems, and the congestion management of distribution systems. He is co-work package leader of the first large scale demonstration project related to EV integration into power systems (WP2 of the EDISON project). Within this he is the main contributor on tasks of EV system architecture design, the potential of using EVs to provide ancillary services, and network impact of EVs on distribution and transmission systems. He has also worked on congestion management of distribution systems with large scale EV integration. Professor Wu gave a tutorial on "smart charging for electric vehicle(EV) fleet operators (FOs) and ICT implementation using IEC 61850" in the ISGT Europe 2011 conference. He contributed a chapter to the large edited book Modeling and Control of Sustainable Power Systems: Towards Smarter and Greener Electric Grids (Springer, 2011).

Contributors xi Preface xiii 1 Electrification of Vehicles: Policy Drivers and Impacts in Two Scenarios 1 M. Albrecht, M. Nilsson and J. Akerman 1.1 Introduction 1 1.2 Policy Drivers, Policies and Targets 2 1.2.1 Finland 6 1.2.2 Sweden 7 1.2.3 Denmark 8 1.2.4 Norway 10 1.2.5 Nordic Comparison 10 1.3 Scenarios and Environmental Impact Assessment 11 1.4 Future Policy Drivers for a BEV and PHEV Breakthrough 16 1.4.1 Entrepreneurial Activities 18 1.4.2 Knowledge Development and Knowledge Diffusion 19 1.4.3 Positive External Effects 19 1.4.4 Resource Mobilization 19 1.4.5 Guidance 20 1.4.6 Market Creation 20 1.4.7 Creation of Legitimacy 23 1.4.8 Materialization 23 1.5 Results and Conclusion 24 Acknowledgements 25 References 25 2 EVs and the Current Nordic Electricity Market 32 C. Bang, C. Hay, M. Togeby and C. Sondergren 2.1 Chapter Overview 32 2.2 Electricity Consumption by EVs 33 2.2.1 Typical Consumption of an EV 33 2.2.2 Potential Challenges for Electrical Grids 33 2.3 Market Actors 37 2.3.1 Electricity Consumer: Individual Vehicle Owner 37 2.3.2 DSO/Grid Company 38 2.3.3 Retailer 38 2.3.4 Generator 38 2.3.5 Fleet Operators 38 2.3.6 TSO 39 2.3.7 Nord Pool 39 2.4 Nordic Electricity Markets 39 2.4.1 The Spot Market and the Financial Market 40 2.4.2 Elbas Market (Intraday) 41 2.4.3 Regulating Power Market 42 2.4.4 Future Development of the Nordic Regulating Power Market 44 2.5 Electricity Price 44 2.5.1 Composition of End-User Price 44 2.5.2 Fixed Tariffs for Losses 45 2.5.3 Transport and Local Congestions 45 2.5.4 Taxes 46 2.5.5 Future Tariff Possibilities 46 2.6 Electricity Sales Products for Demand Response 46 2.6.1 Fixed Price 46 2.6.2 Time-of-Use Products 46 2.6.3 Critical Peak Pricing 47 2.6.4 Spot Price 47 2.6.5 Future Contract Possibilities Including Regulating Power Market 48 2.7 EVs in Different Markets 48 2.7.1 Contract Structure 1: The Current Spot Market 49 2.7.2 Contract Structure 2: The Spot Market and Regulating Power Market 50 2.7.3 Contract Structure 3: EVs Controlled by a Fleet Operator 52 2.7.4 Summary 52 References 53 3 Electric Vehicles in Future Market Models 54 C. Sondergren, C. Bang, C. Hay and M. Togeby 3.1 Introduction 54 3.2 Overview 54 3.2.1 Spot Market 55 3.2.2 Regulating Power Market 55 3.2.3 Automatic Reserves 55 3.2.4 Congestions in the Distribution Grid 55 3.2.5 Role of the Distribution System Operator 56 3.3 Alternative Markets for Regulating Power and Reserves for EV Integration 56 3.3.1 The Regulating Power Market 56 3.3.2 Market for Automatic Reserves 58 3.3.3 Proposal from the Danish TSO on Self-Regulation 58 3.3.4 FlexPower 60 3.3.5 Other Potential Alterations to Regulating Power Market 63 3.3.6 Demand as Frequency-Controlled Reserves 64 3.3.7 Frequency Regulation Via V2G 64 3.4 Alternative Market Models for EV Integration 66 3.4.1 Locational Prices (Nodal Pricing in the Transmission Grid) 66 3.4.2 Complex Bidding 67 3.5 Management of Congestions in the Distribution Grid 69 3.5.1 Section Overview 70 3.5.2 The Role of the DSO 71 3.5.3 Overall Approach: The Order of System Balance and Grid Congestions 72 3.5.4 Payment for the Right to Use Capacity 74 3.5.5 Variable Tariffs (Time of Use) 75 3.5.6 Progressive Power Tariffs 75 3.5.7 Direct Control: Regulatory Management 76 3.5.8 Bid System 76 3.5.9 Dynamic Distribution Grid Tariffs 77 3.5.10 Comparison 79 3.5.11 Operation of a VPP for EVs 80 References 81 4 Investments and Operation in an Integrated Power and Transport System 82 Nina Juul and Trine Krogh Boomsma 4.1 Introduction 82 4.2 The Road Transport System 83 4.2.1 Expectations of Future Road Transport System and Integration with Power System 84 4.3 The Energy Systems Analysis Model, Balmorel 84 4.4 Modelling of Electric Drive Vehicles 85 4.4.1 Assumptions 86 4.4.2 Costs 87 4.4.3 Transport Demand 88 4.4.4 Power Flows 88 4.4.5 Variable Load Factor 94 4.4.6 BEVs 94 4.4.7 EDVs Contributing to Capacity Credit Equation 94 4.5 Case Study 96 4.5.1 Vehicle Technologies 96 4.5.2 Driving Patterns/Plug-in Patterns 98 4.6 Scenarios 101 4.7 Results 101 4.7.1 Costs 102 4.7.2 Investments and Production 102 4.7.3 Introducing EDVs 106 4.7.4 Charging the PHEVs 107 4.8 Results from EDVs Contributing to Capacity Credit Equation 108 4.9 Discussion and Conclusion 110 4.10 Summary 111 References 111 5 Optimal Charging of Electric Drive Vehicles: A Dynamic Programming Approach 113 Stefanos Delikaraoglou, Trine Krogh Boomsma and Nina Juul 5.1 Introduction 113 5.2 Hybrid Electric Vehicles 115 5.3 Optimal Charging on Market Conditions 115 5.4 Dynamic Programming 117 5.5 Fleet Operation 118 5.6 Electricity Prices 119 5.6.1 A Markov Chain for Electricity Prices 119 5.6.2 The Price--Load Dependency 119 5.7 Driving Patterns 120 5.7.1 Vehicle Aggregation 120 5.8 A Danish Case Study 121 5.9 Optimal Charging Patterns 122 5.9.1 Single Vehicle Operation 122 5.9.2 Vehicle Fleet Operation 125 5.10 Discussion and Conclusion 127 Acknowledgments 128 References 128 6 EV Portfolio Management 129 Lars Henrik Hansen, Jakob Munch Jensen and Andreas Bjerre 6.1 Introduction 129 6.2 EV Fleet Modelling and Charging Strategies 130 6.2.1 System Set-up 130 6.2.2 Battery Modelling 132 6.2.3 Charging Strategies 132 6.3 Case Studies of EV Fleet Management 140 6.3.1 System Description 140 6.3.2 Scenario Description 145 6.3.3 Conclusions on the Case Studies of the Charging Strategies 151 6.3.4 Future Implications 152 References 152 7 Analysis of Regulating Power from EVs 153 Qiuwei Wu, Arne Hejde Nielsen, Jacob Ostergaard and Yi Ding 7.1 Introduction 153 7.2 Driving Pattern Analysis for EV Grid Integration 154 7.2.1 Driving Distance Analysis 154 7.2.2 EV Availability Analysis 154 7.3 Spot-Price-Based EV Charging Schedule 158 7.3.1 EV Charging Schedule Based on Spot Price 160 7.3.2 Intelligent Charging Schedule Based on Spot Price 164 7.4 Analysis of Regulating Power from EVs 165 7.4.1 Regulating Power Requirement and Price Analysis 165 7.4.2 Analysis of Regulating Power Capacity from EV Grid Integration 168 7.4.3 Economic Return from Regulating Power Provision by EVs 174 7.5 Summary 176 References 176 8 Frequency-Control Reserves and Voltage Support from Electric Vehicles 178 Jayakrishnan R. Pillai and Birgitte Bak-Jensen 8.1 Introduction 178 8.2 Power System Ancillary Services 179 8.3 Electric Vehicles to Support Wind Power Integration 179 8.4 Electric Vehicles as Frequency-Control Reserves 181 8.4.1 Primary Reserves 182 8.4.2 Secondary Reserves 185 8.4.3 Tertiary Reserves 188 8.5 Voltage Support and Electric Vehicle Integration Trends in Power Systems 189 8.6 Summary 189 Acknowledgements 190 References 190 9 Operation and Degradation Aspects of EV Batteries 192 Claus Nygaard Rasmussen, Soren Hojgaard Jensen and Guang Ya Yang 9.1 Introduction 192 9.2 Battery Modelling and Validation Techniques 193 9.2.1 Background 194 9.2.2 Experimental Testing Techniques 195 9.2.3 Degradation of Battery Modules 206 9.2.4 Test Set-Up and Results 207 9.3 Thermal Effects and Degradation of EV Batteries 209 9.3.1 Introduction to Battery Degradation 210 9.3.2 Theoretical Background 210 9.3.3 Modelling Degradation Effects 214 9.3.4 Simulation of EV Use 216 9.4 Electric EC Model 221 9.4.1 Battery Modelling: Dynamic Performance 221 9.4.2 Battery Cell Models Described in the Literature 222 9.4.3 Battery Model Implementation in Matlab 224 9.4.4 Model Parameterization and Validation 228 References 231 10 Day-Ahead Grid Tariffs for Congestion Management from EVs 233 Niamh O'Connell, Qiuwei Wu and Jacob Ostergaard 10.1 Introduction 233 10.1.1 Power System Congestion 234 10.1.2 Coordinated EV Charging 235 10.2 Dynamic Tariff Concept 238 10.2.1 DT Framework 240 10.2.2 DT Calculation 240 10.2.3 Optimal EV Charging Management 244 10.3 Case Studies 246 10.3.1 Vehicle Driving Data 246 10.3.2 EV Cohort Characteristics 248 10.3.3 Price Profiles 248 10.3.4 Electrical Network 249 10.3.5 Software and Case Study Parameters 249 10.3.6 Case Study Results 250 10.4 Conclusions 256 References 257 11 Impact Study of EV Integration on Distribution Networks 259 Qiuwei Wu, Arne Hejde Nielsen, Jacob Ostergaard and Yi Ding 11.1 Introduction 259 11.2 Impact Study Methodology and Scenarios 260 11.2.1 Grid Model for EV Grid Impact Study 260 11.2.2 Demand Data 261 11.2.3 EV Demand Data 261 11.2.4 EV Distribution Over the Grid 261 11.2.5 Loading Limits 262 11.2.6 Limitations 263 11.3 Bornholm Power System 263 11.3.1 Overview of Bornholm Power System 263 11.3.2 Bornholm Power System Model in PowerFactory 264 11.4 Conventional Demand Profile Modeling 268 11.5 Impact Study on 0.4 kV Grid 270 11.6 Impact Study on 10 kV Grid 276 11.7 Impact Study on 60 kV Grid 280 11.8 Conclusions 284 References 285 Index