COGenerator

A cogenerator, or cogeneration unit, is a system that simultaneously produces electricity and usable heat from a single energy source. It is a form of combined heat and power (CHP) installation designed to improve overall energy efficiency.

The core components include a prime mover—such as an internal combustion engine, a gas turbine, or a steam turbine—coupled to an electrical generator. The heat rejected by the prime mover, via exhaust or cooling circuits, is captured by a heat recovery system to provide space heating, hot water, steam, or process heat. This arrangement recovers energy that would otherwise be wasted in conventional power generation.

Cogeneration spans scales from micro-CHP units for homes and small buildings to large industrial CHP plants and district heating networks. It is used in hospitals, universities, manufacturing facilities, and commercial buildings, particularly where there is a substantial and continuous heat demand.

Efficiency and economics: Electrical efficiencies typically range from 25% to 45%, with heat recovery adding 30% to 60% or more, yielding overall system efficiencies often between 65% and 90% when heat is effectively utilized. Benefits include higher fuel efficiency, reduced emissions per unit of energy, and greater resilience of power and heat supply. Drawbacks include higher capital cost, increased system complexity, and a need for a steady heat load and reliable fuel supply.

History and significance: Cogeneration has deep roots in the early 20th century and gained prominence during energy crises as a means to improve energy efficiency and reduce emissions. It remains a mature technology with ongoing developments in biogas, hydrogen, and modular micro-CHP systems. See also combined heat and power, district heating, waste heat recovery.