Adopting combined heat and power (CHP)
Combined heat and power generates electricity on site and captures the heat that would otherwise be wasted, using it for process or space heating. By making two useful outputs from one fuel input, a well-matched CHP unit reaches far higher overall fuel utilisation than separate grid power and a boiler, cutting both cost and emissions.
What it is
A CHP, or cogeneration, plant runs an engine or turbine to produce electricity and recovers the exhaust and cooling heat as hot water or steam. Adopting it means sizing the unit to a site's coincident heat and power demands so that both outputs are genuinely used. The defining feature is that the heat, normally rejected in central power generation, becomes a primary product.
Why it is done
Generating electricity centrally throws away most of the fuel energy as waste heat at the power station; making power on site lets that heat be used. Where a plant has a steady, year-round heat demand alongside its electrical load, CHP raises overall fuel-to-useful-energy efficiency dramatically, reduces exposure to grid prices, and can lower carbon emissions — provided the recovered heat is actually consumed.
How it is done
The site's heat and electricity demand profiles are characterised, with particular attention to how many hours both are needed together, because CHP economics live or die on heat use. A unit is sized to the heat demand — not the electrical peak — so the recovered heat is always absorbed, and electricity becomes the by-product. The plant is integrated with the heating system and grid connection, controlled to follow heat demand, and its overall efficiency verified against the heat actually used.
- Profile heat & power demand
- Find coincident hours
- Size to heat demand
- Integrate heat & grid
- Control to follow heat
- Verify heat utilisation
What to watch for
Sizing CHP to the electrical load rather than the heat demand leaves heat dumped and the efficiency case collapsing. Running a unit through periods with no heat sink turns it into an expensive, inefficient generator no better than the grid.
Related practices
Switching a boiler from fossil fuel to biomass
Integrating an industrial heat pump
Electrifying process heat
Related topics
Factory Decarbonization: A Practical Roadmap · CHP / Cogeneration · Net Zero · Specific Energy Consumption (SEC)
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