A comparison between distributed generation and utility plants: Technical, economic and environmental aspects

Cogeneration is generally used in the heat and power configuration; the trigeneration includes the production of cooling energy from the prime motor heat recovery, the distributed generation is thus able to meet different energy requirements whether it be electricity, heat and cold. Utility plants only produce electricity and need cooling media such as river or sea water. Under an optimal deployment standpoint, distributed cogeneration means energy cost saving for the end user and primary energy saving for the country where the plant is installed. Besides, environmental advantages should be reached in terms of pollution reduction, reduction of the landscape impact and possibility of using renewable sources. The increase of utility plants efficiency, up to 60% in large combined cycle power plants (GTCC), may jeopardize the advantages associated with distributed generation. This can occur even in the case of cogeneration, when heat recovery is not thoroughly designed and exploited. This paper reports a comparison between distributed generation (both cogeneration and trigeneration) and utility plants, by looking at technical, economic and environmental aspects under different working conditions.