Author: Fergus Cawley, senior electrical projects engineer, Biop
Combined heat and power (CHP), also known as cogeneration, involves the simultaneous production of heat and electrical power from the same source of fuel, usually natural gas. The CHP consists of a gas-fuelled reciprocating engine, a generator/alternator, and a heat recovery system capturing exhaust gas and engine heat.
A CHP uses the by-product heat that is normally discharged to the atmosphere resulting in a higher thermal efficiency. This leads to reduced energy costs and, as a result, CHP engines have a lower rate of carbon dioxide (CO2) emissions per megawatt (MW) of useful energy produced. The heat harnessed from the machine is available as low-pressure hot water and steam.
A CHP unit also offers greatest benefits where the heat load is large and constant throughout the year and makes excellent economic sense when the ratio of grid electricity prices to gas prices per kWh are high. A brief explanation of all key elements to consider are detailed bellow: