DOE EERE Research Reports
Distributed Energy Resources (DER) and Combined Cooling, Heating, and Power (CHP)
Electric power is delivered to American homes and businesses at an overall efficiency of about 30%. Almost 70% of the energy content
of the fuels delivered to power plants throughout the country is lost into cooling waters from rivers and lakes or into the atmosphere.
Distributed energy resources (DER) seek to improve upon this low efficiency by situating "small" electric generators close to
the homes and businesses served. Distributed energy resources are typically natural gas or diesel fuel-fired generators and can range in
capacity from several kilowatts to well over a megawatt. Locating DER generation close to the consumer eliminates the transmission and distribution
losses typically experienced in distributing power to consumers (a 10% loss).
While distributed energy resources (DER) recoups some energy losses, tremendous amounts of heat are still rejected to the environment.
Combined cooling heating and power (CHP) combines generator heat recovery with customer heating and cooling loads. Comnbined cooling heating and power (CHP)
incorporates a natural gas-fired electric generator next to the customers building with heat recovery from the engine exhaust and/or engine-jacket and lube oil
cooling water. This heat can be used directly for space heating and service hot water needs. Recovered heat in a CHP system can also be used to drive an absorption chiller
to produce chilled water for air conditioning or to regenerate the desiccant used in desiccant dehumidification. Combined cooling heating and power (CHP) systems
have demonstrated overall efficiencies in excess of 80%, providing a nice boost to gains provided by DER.