What is cogeneration (CHP)? How combined heat and power uses natural gas more efficiently, and where it fits in Georgia.
Cogeneration — usually called combined heat and power, or CHP — means generating electricity and useful heat from a single fuel input, at the place where both are used. It sounds technical, but the underlying idea is simple: conventional power generation throws away most of the energy in the fuel as waste heat, and cogeneration refuses to.
A traditional power station burns fuel, spins a turbine and sends electricity down the wires. Roughly half to two-thirds of the energy in that fuel leaves as heat through cooling towers or exhaust, and more is lost in transmission before it reaches you. The electricity is useful; the heat is simply discarded, because the plant is too far from anyone who could use it.
A cogeneration system puts the generator on site. The electricity powers the building, and the waste heat — which would otherwise vent to the sky — is captured for space heating, hot water, or an industrial process. One fuel input, two useful outputs.
Conventional generation delivered to a customer commonly lands somewhere around 35–45% overall efficiency once transmission losses are counted. A well-matched CHP system can reach 65–80% because it uses both outputs and avoids most transmission loss.
The critical qualifier is well-matched. CHP only delivers that efficiency when there is a genuine, steady demand for the heat. A site that needs electricity but has nowhere to put the heat gains little, because the heat is discarded again and you are back to ordinary generation.
Most natural gas CHP installations consist of a prime mover — a reciprocating engine, turbine or microturbine — driving a generator, with heat recovery equipment capturing energy from the exhaust and cooling system. That heat feeds hot water, steam or space heating. Some systems add absorption chillers that use heat to produce cooling, which extends useful operation into summer and is called trigeneration.
CHP suits facilities with simultaneous, sustained demand for power and heat:
Residential-scale micro-CHP exists but remains uncommon in the United States, largely because a typical home’s heat demand is too seasonal and intermittent to justify the equipment.
Georgia has significant industrial and institutional gas demand, and CHP shows up as a way for large users to cut energy costs and improve resilience. For a facility that cannot tolerate an outage, on-site generation is valuable beyond the efficiency gain. Large gas users contract differently from households — typically on commercial terms rather than the residential plans listed on this site.
CHP is almost certainly not something you will install. The transferable idea is the one worth keeping: efficiency is about capturing energy you are already paying for rather than buying more. At home that means sealing leaks, insulating, and maintaining appliances — see energy conservation tips and how gas appliances work.
And on the purchasing side, make sure you are buying therms at a competitive price: compare current Georgia natural gas rates. Related: recycled natural gas and gas vs electric.