December 9, 2009 / 2:00 AM / 10 years ago

UK ground pumps could meet third of green heat aim

LONDON (Reuters) - Ground source heat pumps (GSHP), a technology which pumps liquid through underground coils to absorb heat, could supply a third of Britain’s renewable heat target by 2020, the Environment Agency said on Wednesday.

The two main principles behind GSHP are the closed loop system, which involves pumping water and antifreeze through coils buried a few metres underground, and an open loop system, which uses water from an underground wells in the coils.

Because the temperature underground is warmer, the liquid is heated and energy can be transferred to where it is needed, such as offices and homes.

GSHP can be reversed and turned into heat sink to cool building in the summer when underground temperatures drop.

A growth forecast indicates 320,000 units could be installed by 2020, up from 8,000 in 2009, which would equate to 1 percent of homes and 11 percent of commercial buildings, the government agency said in a report.

“The growth scenario alone would generate 30 percent of the amount of renewable heat that government has said will be required to meet the UK’s 2020 renewable energy target,” it said.

At the upper end, the agency estimated up to 1.2 million GSHP units could be installed over the same period, equating to an increase of 150 times and representing 11 percent of homes and 40 percent of commercial buildings.

“Ground source heating is a rapidly growing technology... but it needs financial support in order to grow,” Tony Grayling, head of climate change and sustainable development, said.

Hurdles hindering growth included the high initial installation costs of GSHP compared with conventional gas boilers, especially when retro-fitted to buildings.

“The initial capital costs are more than for a normal boiler, but the GSHP would be cheaper to run,” a spokeswoman for the Environment Agency said. The report estimates GSHP would generate three to four times the amount of energy used to run the system.

A way of overcoming these barriers would be the government’s Renewable Heat Incentive, which will be introduced in 2012 and would pay homes and business for generating renewable heat, the agency said.

According to the Environment Agency, the number of installed GSHP units doubled to 8,000 in 2009 from last year, and domestic units have enough capacity to provide heat and hot water for a typical home.

GSHP are different to geothermal heat technology, which drives liquid much deeper underground to transfer heat to the surface.

Reporting by Kwok W. Wan

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