The UK is set to get its first commercial scale geothermal power plant. Geothermal Engineering has announced plans to build a 65MW plant in Redruth, Cornwall, and has begun consultation with the local community.
The plans involve drilling two 4.5km deep wells using 50m rigs. Temperatures at these depths are expected to exceed 170ºC. Water will be pumped down into the rock, where it will be naturally heated, before being pumped back to the surface as hot water or steam.
Heated water will be used to power turbines to generate electricity and as a renewable heat source.
The scheme will generate 55MW for local uses. It will also supply 10MW to the national grid.
The Hot Dry Rock research project, carried out in Cornwall from 1976 to 1991, showed the location was suitable for geothermal energy generation. The ground material is sufficiently permeable to make the scheme commercially viable.
“The challenge is ensuring the figures stack up,” said Ryan Law, managing director of Geothermal Engineering, who spent 10 years pioneering geothermal energy within Arup’s geotechnics department.
“There is a substantial capital cost involved so the payback must be worth it, so we must be able to drive water down into the rock and draw it back up without it being too energy intensive,” added Law.
The Redruth plant will cost £40M to build. The Department for Energy and Climate Change (DECC) has committed £6M funding into harnessing geothermal power, which Law hopes to exploit. Private financiers will supply the bulk of the capital.
Geothermal energy is already being successfully used in the US, Germany, Australia, New Zealand and Iceland.
“The UK is on the back foot,” said Law. “Government funding in the sector has catapulted development in Germany and the US. Finally the UK Government has invested in this technology. David Cameron has also promised to give it a shot in the arm if the Conservatives win power.
“We have an unlimited energy resource under our feet, ready to be harnessed.”
Drilling will start in mid 2010, with the plant commercially operational by 2013.
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