The traditional model of regulated central utility plants generating bulk electric power and transmitting it to municipal distribution grids has been steadily encroached upon in recent years by a new concept; the distributed generator. Under this emergent model, two principal features are evident. The first is that the localized generator is dedicated to a single customer load or a physically restricted load; say that of a school campus. The second feature is the recovery of the generator waste heat to offset fuel consumption in other thermal processes in the local facility. The result is very high total cycle efficiency that results in an overall reduction of facility energy costs.
This form of co-generation, as it is called, can range from plants of several megawatts capacity, that commonly service hospitals or university campuses, to small-scale units of several tens of kilowatts that can service a single load, say a municipal indoor swimming pool. The use of co-generation can also run chilling equipment using the waste heat of the co-generator as the chiller’s energy source. In this case, the technology is referred to as tri-generation of combined cooling, heating and power (CCHP).