Combined heat and power
Combined heat and power, or CHP, generates electricity and captures useful heat from the same fuel or energy source instead of wasting that heat.
What combined heat and power is
Combined heat and power is an energy system that produces electricity or mechanical power and useful thermal energy from a single source. Instead of throwing away heat from power generation, CHP captures it for steam, hot water, space heating, process heat, domestic hot water, or cooling through absorption chillers.
How it works
A prime mover such as a gas turbine, reciprocating engine, steam turbine, microturbine, or fuel cell generates power. Heat exchangers or recovery equipment then capture heat from exhaust, cooling systems, or steam flows and send that heat to a useful load.
Why heat demand matters
CHP only makes sense when the recovered heat can be used. Hospitals, campuses, factories, wastewater treatment plants, district energy systems, food processors, refineries, and large buildings can be good candidates because they often need steady electricity and thermal energy together.
Common configurations
One common design uses a combustion turbine or engine to generate electricity and a heat recovery unit to make steam or hot water. Another uses a boiler to make steam, sends that steam through a turbine for power, and then uses lower-pressure steam for heating or industrial processes.
District energy and microgrids
CHP can serve one building, one industrial site, or a network of buildings. In district heating or district cooling, a central plant can distribute thermal energy through pipes. In a microgrid, CHP may also support resilience by keeping critical loads powered during some grid outages.
Efficiency and emissions
CHP can achieve higher total efficiency than separate heat and power when it is correctly sized and operated. Emissions benefits depend on the fuel, operating pattern, displaced grid electricity, displaced boilers, local air rules, maintenance, and whether the system can adapt as the electric grid gets cleaner.
Limits and tradeoffs
CHP is not automatically clean or economical. It can require high capital cost, fuel supply contracts, skilled maintenance, air permits, interconnection agreements, thermal distribution equipment, and careful controls. A poorly matched system may dump heat, run too few hours, or lock a site into fossil fuel use longer than planned.
Why it matters
CHP sits at the overlap of electricity, heating, industrial energy, and resilience planning. It can reduce wasted heat in facilities with steady demand, but it also forces a careful question: which energy services should be produced locally, which should come from the grid, and how should systems evolve as low-carbon power, heat pumps, storage, and renewable fuels expand?