Ground source heat pumps that tap heat stored underground could provide as much as one-third of the UK’s renewable heating needs, a new report from the Environment Agency has found.

Also known as geothermal heat pumps, ground source heat pumps (GSHPs) take advantage of the heat stored underground in winter, as well as the ground’s cooler temperatures in summertime, to provide hot water and heating or cooling for buildings.

The technology is already commonplace in other European countries like Sweden. Although the UK lags behind, the market is rapidly expanding, with installations doubling in the last year alone, according to the Environment Agency.

The pumps have become increasingly popular in London, where developers have installed them to meet the Merton Rule, which requires large developments to build some on-site renewable energy generation.

While there are currently just 8,000 or so ground source heat pumps in the UK, that number could rise to over one million with sufficient government support, the Environment Agency report finds. It states the Renewable Heat Incentive — which will be introduced in 2012 and will pay homeowners and businesses a guaranteed price for generating renewable heat — will be the most important factor in determining how much the GSHP industry grows.

“Ground source heating is a rapidly growing technology that has the potential to produce at least 30 per cent of the country’s renewable heat needs, but it needs financial support in order to grow,” said Tony Grayling, head of Climate Change and Sustainable Development at the Environment Agency. “We would like to see this technology given adequate financial support through the new renewable heat incentive to meet its full potential in the UK.”

Grayling added, “We have ambitious emissions reduction targets in UK, and the Environment Agency would like to see rapid growth of all low-carbon energy technologies to help meet these. Any delays in reducing emissions will lead to more severe impacts of climate change.”

The Environment Agency report, “Ground source heating and cooling pumps: state of play and future trends,” found that:

• The UK market for GSHPs doubled last year, with 4,000 new units installed.
• The majority of GSHPs are domestic units with a capacity of 4 to 12 kilowatt-hours — enough to provide a typical home with heating and hot water.
• There has been considerable growth of GSHPs in London, with open loop pumps being used to cool offices.
• Heat pumps are not carbon neutral, as they need electricity to drive the pump, but they typically generate three or four times the energy used to drive the system.
• In  the “growth” scenario, the UK could have 320,000 GSHPs installed by 2020, affecting 1 per cent of homes and 11 per cent of commercial buildings.
• In a “high-growth” scenario, up to 1,200,000 units could be installed, heating 11 per cent of homes and 40 per cent of commercial buildings in the UK. This represents the extreme end of what could be possible.
• The UK electricity distribution network would need to be upgraded in many instances to allow the installation of larger heat pumps.

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