Combined Heat and Power (CHP)

ABOVE: The Dachs from Baxi SenerTec UK is currently the only CHP unit that is even close to domestic scale. It is more suited to light commercial properties, but can be used on larger luxury houses with swimming pools. However, Baxi is currently working on the EcoGen – due to be launched next year – which aims to provide CHP specifically for domestic properties

Combined heat and power – or CHP – means producing both heat and electricity from the same fuel. The technology is very similar to a car engine. Fuel (typically oil or natural gas) is fed into an engine, which powers a generator producing electricity. As with a car engine, a CHP unit also produces heat which is captured and then used to heat the building.

The balance of the amount of electricity produced to the amount of heat is often critical, in as much as if you can’t use a good proportion of both the heat and electricity, CHP stops being economically viable.

The only unit currently available getting anywhere close to domestic scale is the Dachs available from Baxi-SenerTec UK. It will produce 5.5kW of three-phase electrical power and between 12.5-15.5kW of usable heat each hour. In that period it will consume 22.8kWh of gas. The cost of that fuel (assuming it is natural gas) will be £1 and the value of the electricity and heat produced £1.26. If the unit is run for eight hours per day it will produce 14,600kWh of electricity and 35,040kWh of heat. Three times as much electricity as the house needs and twice as much heat.

Further Reading:

• Saving Energy: A Look at Renewables
• A Guide to Heating & Plumbing
• The Death of Central Heating