Synchronous or induction generators? The choice for small scale generation

From the beginning of this decade, there has been a significant increase in the extent of small scale generation in the UK. This is occurring partly as a consequence of two Government targets, namely to have 5000 MW of combined heat and power (CHP) and 1500 MW of new renewable energy capacity in service by the year 2000. The latter is being implemented through the vehicle of the NFFO (Non-Fossil Fuel Obligation), and its equivalents in Scotland and Northern Ireland. More often than not, this generation is being connected to the distribution network and is termed embedded generation. The exceptions to this are mainly large CHP schemes which are outwith the scope of this paper. This paper offers a timely review of the different operating characteristics of induction and synchronous type generators and highlights the various different technical and economic factors which must be considered when specifying and choosing the type of generators for small scale generation systems.