CHP

Combined Heat and Power (CHP) is the simultaneous generation of usable heat and power (usually electricity) in a single process and use of the technology in the UK is dominated in terms of output by large systems. More than 80% of the total output of all schemes is derived from less than 5% of the total number of installations.*

Micro-CHP may be described as the application of the technology for a small building or residence and is still a developing industry. Small scale biomass fuelled systems are not yet available and gas powered, Stirling engine based systems have yet to become suitable for domestic installation. Relatively small (<20kWe) diesel (&/or bio-diesel) and gas powered, generator based systems are now available for large domestic or small commercial installations.

CHP offers the double benefit of making more efficient use of the energy used to generate electricity, and of reducing infrastructure and distribution costs by placing the generating capacity where the output is to be used. However, CHP is not necessarily appropriate for all installations and its suitability should be considered carefully on a site by site basis.

Key criteria in the decision to install CHP include:

• Running time: in order to be cost effective the system ideally needs to run for a minimum of 4,500 hours/year.
• Total capital cost
• The capital cost per kW of output
• The ability to use the heat generated by the CHP system
• Fuel price is critical to the economic viability of CHP
• The relative price of the fuel used to the price of electricity and heat produced from other sources
  
  *  DTI’s 2006 Digest of UK Energy Statistics

Output

Electricity and heat from 4kW/8kW to 49kW/90kW

Fuel Type

Heating oil, rapeseed oil, natural gas