Distributed and dispersed generation: addressing the spectrum of consumer needs

Distributed generation (DG) entails using many small generators, of 2-50 MW output, situated at numerous strategic points throughout cities and towns, so that each provides power to a small number of consumers nearby. While these small generators might be solar or wind turbine units, generating units in this category are most often highly efficient gas turbines in small combined cycle plants, because these are the most economical choices. Although small compared to traditional central station generators, such 2-500 MW generating units are large, both physically and electrically compared to the needs of individual energy consumers, producing power for between 50 and 400 homes. Dispersed generation refers to use of still smaller generating units, of less than 500 kW output and often sized to serve individual homes or businesses. These units are small enough to fit into garages or, like central air-conditioners, on a pad behind a house. Micro gas turbines, fuel cells, diesel, and small wind and solar PV generators make up this category.