Combined Heat and Power (CHP) is the simultaneous and sequential generation of multiple forms of useful energy from a single fuel source in a single integrated system. The useful energy is usually in the form of mechanical and thermal.
Boiler-based CHP systems burn fuel in a boiler to create high-pressure steam, which powers a turbine that, in turn, drives a generator to produce electricity. The steam can be used to provide heat for an industrial process or to heat buildings in the vicinity. Steam turbines are well-suited to medium- and large-scale industrial sites that would already use boilers.
Gas turbine- or engine-based CHP systems burn fuel―typically natural gas―directly in a turbine or engine that drives the electricity generator. Hot exhaust gas from the engine enters a boiler that creates steam or hot water for industrial uses or for space heating. This configuration is ideally suited to sites requiring ample amounts of both electricity and heat.