Scales of combined heat and power technologies

This page shows the different scales at which CHP can be used.

Three scales of CHP

Internal combustion engine micro-CHP unit

Micro CHP

Internal combustion engine micro-CHP unit with hot water storage tank to enable continuous operation.

CHP unit at Dalston Square

Development scale

Packaged CHP at Dalston Square in East London.The unit is housed in an insulating enclosure to minimise noise levels.

Large scale CHP

Large scale

The visual impacts of large scale CHP can be significantly reduced through good design offering an improvement to traditional power stations.

Technologies, installations and applications

The main generation technologies (internal combustion engine, steam turbine, gas turbine, stirling engine and micro-turbines) are used at different scales. These scales are applicable to different installation types.

Scale: Micro and mini CHP (from 1kWe)

Technologies Stirling engines
Internal combustion engine
Organic rankine cycle (not yet commercially available at this scale)
Fuel cell (unlikely to be commercial before 2012 according to technology developers)
Micro CHP is a relatively new technology which is still being tried and tested.
Fuel Natural gas
Efficiency Fuel conversion efficiency of up to 80 per cent.
Applications Replacing gas boilers in individual homes and small buildings and generating some or all of the electricity needs.
Installations Micro-CHP systems are designed and supplied as complete units. They contain the engine, generator and heat recovery equipment, together with all the associated pipework, valves and controls. In some cases thermal store is supplied along with the unit.
Although systems are commercially available, CHP technology at this scale is still maturing.

Scale: Building level CHP (60kWe to 1.5MWe)

Technologies Internal combustion engines
Organic rankine cycle
Fuel Natural gas
Biogas and liquid biofuels
Fuel oils
Efficiency Mature and reliable technology with fuel conversion efficiency of up to 85 per cent.
Applications Supplying some or all heat and electricity for commercial and public buildings as well as blocks of flats and small to medium developments, via a heat network.
Installations As with micro/mini systems, packaged CHP systems are designed and supplied as complete units to meet the requirements of the site and its energy demands.

Scale: Large scale CHP (1MWe to hundreds of MWe)

Technologies Internal Combustion Engines
Gas turbines
Fuel Natural gas
Biogas and liquid biofuels
Fuel oils
Coal, lignite or coke
Efficiency Overall fuel conversion efficiencies range between 70 and 85 per cent.
Applications Central CHP system supplying some or all heat and power to multiple buildings (linked by a heat network) or to industry.

Can start with small number of buildings with high and relatively steady heat demand (known as anchor loads) and expand over time.
Installations Specially built plant that generally consists of large and complex systems installed onsite.

Further explanation about heat demand, locations, management, maintenance and the future of CHP are available here:

Opportunities for combined heat and power


1 May 2012

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