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Renewable Energy in Power Systems

Leon Freris, David Infield

ISBN: 978-0-470-98894-7 September 2008 300 Pages


Renewable Energy (RE) sources differ from conventional sources in that, generally they cannot be scheduled, they are much smaller than conventional power stations and are often connected to the electricity distribution system rather than the transmission system.  The integration of such time variable ‘distributed’ or ‘embedded’ sources into electricity networks requires special consideration. 

This new book addresses these special issues and covers the following:

  • The characteristics of conventional and RE generators with particular reference to the variable nature of RE from wind, solar, small hydro and marine sources over time scales ranging from seconds to months
  • The power balance and frequency stability in a network with increasing inputs from variable sources and the technical and economic implications of increased penetration from such sources  with special reference to demand side management
  • The conversion of energy into electricity from RE sources and the type and characteristics of generators used
  • The requirement to condition the power from RE sources and the type and mode of operation of the power electronic converters used to interface such generators to the grid
  • The flow of power over networks supplied from conventional plus RE sources with particular reference to voltage control and protection
  • The economics and trading of ‘green’ electricity in national and international deregulated markets
  • The expected developments in RE technology and the future shape of power systems where the penetration from RE sources is large and where substantial operational and control benefits will be   derived from extensive use of power electronic interfaces and controllers

The text is designed to be intelligible to readers who have little previous knowledge of electrical engineering. The more analytical electrical aspects are relegated to an Appendix for readers who wish to gain a more in depth  understanding. The book’s flexible structure makes its accessible to the general engineer or scientists but also caters for readers with a non-scientific background. Economists, planners and environmental specialists will find parts of the book informative. 




1 Energy and Electricity.

1.1 The World Energy Scene.

1.2 The Environmental Impact of Energy Use.

1.3 Generating Electricity.

1.4 The Electrical Power System.


2 Features of Conventional and Renewable Generation.

2.1 Introduction.

2.2 Conventional Sources: Coal, Gas and Nuclear.

2.3 Hydroelectric Power.

2.4 Wind Power.

2.5 PV and Solar Thermal Electricity.

2.6 Tidal Power.

2.7 Wave Power.

2.8 Biomass.

2.9 Summary of Power Generation Characteristics.

2.10 Combining Sources.


3 Power Balance/ Frequency Control.

3.1 Introduction.

3.2 Electricity Demand.

3.3 Power Governing.

3.4 Dynamic Frequency Control of Large Systems.

3.5 Impact of Renewable Generation on Frequency Control and Reliability.

3.6 Frequency Response Services from Renewables.

3.7 Frequency Control Modelling.

3.8 Energy Storage.


Other Useful Reading.

4 Electrical Power Generation and Conditioning.

4.1 The Conversion of Renewable Energy into Electrical Form.

4.2 The Synchronous Generator.

4.3 The Transformer.

4.4 The Asynchronous Generator.

4.5 Power Electronics.

4.6 Applications to Renewable Energy Generators.


5 Power System Analysis.

5.1 Introduction.

5.2 The Transmission System.

5.3 Voltage Control.

5.4 Power Flow in an Individual Section of Line.

5.5 Reactive Power Management.

5.6 Load Flow and Power System Simulation.

5.7 Faults and Protection.

5.8 Time Varying and Dynamic Simulations.

5.9 Reliability Analysis.


6 Renewable Energy Generation in Power Systems.

6.1 Distributed Generation.

6.2 Voltage Effects.

6.3 Thermal Limits.

6.4 Other Embedded Generation Issues.

6.5 Islanding.

6.6 Fault Ride-through.

6.7 Generator and Converter Characteristics.


7 Power System Economics and the Electricity Market.

7.1 Introduction.

7.2 The Costs of Electricity Generation.

7.3 Economic Optimization in Power Systems.

7.4 External Costs.

7.5 Effects of Embedded Generation.

7.6 Support Mechanisms for Renewable Energy.

7.7 Electricity Trading.


8 The Future – Towards a Sustainable Electricity Supply System.

8.1 Introduction.

8.2 The Future of Wind Power.

8.3 The Future of Solar Power.

8.4 The Future of Biofuels.

8.5 The Future of Hydro and Marine Power.

8.6 Distributed Generation and the Shape of Future Networks.

8.7 Conclusions.


Appendix: Basic Electric Power Engineering Concepts.

A.1 Introduction.

A.2 Generators and Consumers of Energy.

A.3 Why AC?.

A.4 AC Waveforms.

A.5 Response of Circuit Components to AC.

A.6 Phasors.

A.7 Phasor Addition.

A.8 Rectangular Notation.

A.9 Reactance and Impedance.

A.10 Power in AC Circuits.

A.11 Reactive Power.

A.12 Complex Power.

A.13 Conservation of Active and Reactive Power.

A.14 Effects of Reactive Power Flow – Power Factor Correction.

A.15 Three-phase AC.

A.16 The Thévenin Equivalent Circuit.



?The book can also be a handy reference for graduate students, practicing engineers, and academics working on grid integration of RE power generation sources and their management or in the general area of power system planning. In fact, I recommend the book for every field engineer who works in the area of planning, integration, and operation of distributed generation in power systems.? (IEEE Power & Energy Magazine , Sept/Oct 2009 )

?This is an unusually clear and helpful volume that should be a bonus to those working in the field of electric power generation, transmission, or management. Summing Up: Highly recommended.? (Choice, April 2009)

?By the end of this excellent text the reader has a much wider view of the whole system problem.? (International Journal of Ambient Energy, January 2009)

"Freris and Infield?s new volume is a useful addition to the library ? .Readable and should be seriously considered as part of the basic research process for anyone." (Engari, December 2008)

Renewable Energy in Power Systems Visit for materials supporting the book
  • Based upon a successful MSc course at Loughborough University.
  • Considers the operation and structure of a modern electricity market, highlighting the differences between a centrally planned and operated system and a fully deregulated one.
  • Includes many tables, diagrams, worked examples, tutorial questions, model answers and case studies to aid the learning process.
  • Presents an introduction to solid-state switches and the way these switches are combined into AC/DC, DC/AC and AC/AC converters.
  • Discusses the regional and local operational benefits/problems that may result in the distribution network due to the injection of energy from renewables.
  • Presents a critical analysis of the selling prices of electricity.