To ask the Secretary of State for Energy and Climate Change, when her Department last made an assessment of the carbon efficiency of heat pumps in obtaining their power from grid-supplied electricity.
The carbon efficiency of heat pumps which utilise electricity supplied from the national grid is affected by two things:
1) heat pump performance (efficiency) which affects how much electricity is required to run the heat pump; and
2) the carbon content of electricity.
DECC publishes current and future assumptions about the carbon content of the electricity grid in the Green Book Supplementary Guidance: Valuation of energy use and greenhouse gas (GHG) emissions available here: https://www.gov.uk/government/publications/valuation-of-energy-use-and-greenhouse-gas-emissions-for-appraisal.
DECC has commissioned a number of studies looking at the installed performance and carbon effectiveness of heat pumps. As part of the Renewable Heat Premium Payment (RHPP) policy, the installed performance of around 700 domestic heat pumps was monitored. Preliminary results were published in January 2014 and include an estimate of carbon savings:
DECC are also currently monitoring a selection of ground and water source heat pumps installed under the Non-Domestic Renewable Heat Incentive.