Optimising unit commitment in an island power system

The Electricity Supply Board (Ireland) is a vertically integrated electric utility which operates generation, transmission and distribution of electricity in the Republic of Ireland. The power system is not connected electrically to any other and is referred to as an `island´ power system. In common with other island power systems, operational problems are posed as a consequence of the largest generation infeed being a substantial portion of the customer demand and providing for the loss of this infeed can be difficult and costly. Special generation dispatch and unit commitment algorithms are needed in such systems and this paper describes the unit commitment algorithm used by ESB and the framework within which it operates. The special operational constraints in ESB´s power system are described, the relevance of these to the unit commitment problem is indicated and the experience gained in daily operation of the system is discussed