Cogeneration (CoGen), or combined heat and power (CHP) is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat. CHP reduces a facility’s demand for heating and cooling. The impact of CHP systems on energy use is an increase in site energy and a decrease in source energy (as source energy is used to generate kBtu’s on site that would otherwise be source generated). A common use of CHP is for contribution to microgrids and therefore some utilities offer incentives for CHP systems. CHP can reduce the greenhouse gas (GHG) emissions substantially due to captured heat being used for space/water heating.