Deregulation is causing dramatic change in the power industry but little is known about how power systems will function under competition. What are suitable performance objectives? What control designs are required and what economic techniques should be used? This detailed analysis attempts to answer these questions. The authors provide a modelling, analysis and systems control framework that makes it possible to relate distinctive features of the electric power industry to more conventional supply/demand processes in other industries. Some parts of the system can be distributed while other parts must remain co-ordinated. This authoritative and detailed study is highly topical and will be of interest to those working in the systems control area, especially in electrical power. It is also most relevant for industrial economists as well as academics in electrical power engineering.