List of Figures and Tables ix List of Contributors xiv Preface xix Acknowledgements xxi List of Acronyms and Abbreviations xxii 1 Variable Renewables and the Grid: An Overview Michael Laughton 1 Introduction 1 Renewable energy source variability 2 Grid operational requirements 11 Base-load capacity displacement with increasing wind penetration 14 Conclusions 27 2 Wind Power on the Grid David Milborrow 31 Introduction 31 Electricity system operation 31 Wind characteristics 36 Managing a network with wind 38 Capacity credits 41 Total extra costs of wind energy 45 Wind energy penetration levels above 20 per cent 47 The influence of national and regional differences 49 Conclusions 51 3 Renewable Resource Characteristics and Network Integration Graham Sinden 55 Introduction 55 Renewable electricity generation in the UK 55 Characteristics 58 Renewable electricity supply and demand patterns 63 The role of wind power in providing capacity on electricity networks 67 Conclusions 71 4 The UK Energy Research Centre Review of the Costs and Impacts of Intermittency Robert Gross Philip Heptonstall Matthew Leach Jim Skea Dennis Anderson Tim Green 73 Introduction 73 Power system reliability and operation 74 Misconceptions and sources of controversy 77 Quantitative findings on impacts and costs 79 Summary of findings and conclusions 86 5 Wind Power Forecasting Bernhard Lange Kurt Rohrig Florian Schlöet;gl Üet;mit Cali Rene Jursa 95 Introduction 95 Applications of wind power forecasting 97 Steps in a forecasting system 97 Numerical weather prediction 98 Different approaches to the power output forecast 99 Forecasthorizon 101 Regional upscaling 103 Smoothing effect 105 Forecast accuracy 107 Example: The Wind Power Management System (WPMS) 110 'Learning curve' of forecasting accuracy 112 Examples of current research 113 Future challenges 117 6 Flexibility of Fossil Fuel plant in a Renewable Energy Scenario: Possible Implications for the UK Fred Starr 121 Introduction 121 The UK power plant system of today 123 Advanced generating plants, energy savings and the issue of climate change 124 Design and operation of coal- and natural gas-powered steam plants 125 Pseudo-intermittency with today's plants 130 Effects on plant components and reliability 132 Intermittency and power plants of the future 136 Conclusions 140 7 The Potential Contribution of Emergency Diesel Standby Generators in Dealing with the Variability of Renewable Energy Sources David Andrews 143 Introduction: Wessex Water 143 The National Grid Transco Frequency Service 143 The National Grid Transco Reserve Service 144 Reserve and standby generating capacity on the UK National Grid 144 'Triads': A revenue-earning opportunity 146 Other benefits: Testing diesels off load 147 8 Demand Flexibility, Micro-Combined Heat and Power and the 'Informated' Grid Bob Everett 151 Introduction 151 What is needed 152 What is on offer 153 Metering and the future 155 9 A Renewable Electricity System for the UK Mark Barrett 157 Introduction 157 Scenario context 159 A sustainable electricity system 162 System integration and optimization 167 Conclusions 178 10 Reliable Power, Wind Variability and Offshore Grids in Europe Brian Hurley Paul Hughes Gregor Giebel 181 Where are the wind resources? 181 What happens when the wind does not blow? 183 The reliability of dispersed offshore wind power 187 Effect of wind farm power output forecasting 190 Delivered cost estimates for new grid and wind farms 190 Results for Europe 193 A Project for Europe: European-wide Supergrid 194 Conclusions 198 11 Planning for Variability in the Longer Term: The Challenge of a Truly Sustainable Energy System David Infield Simon Watson 201 Introduction 201 Renewable source-dominated energy supply systems 202 Energy storage and demand-side management 204 Conclusions and further research 209 Index 211