Natural heat from granite under Cornwall will be tapped to drive turbines at Britain’s first deep geothermal power station. Drilling began yesterday at a site near Redruth that will become this country’s deepest onshore well, reaching hot rocks at a depth of 2.8 miles (4.5km). Water will be pumped down a shallower well 1.5 miles deep and trickle through natural faults to hot rocks around the deeper well. The rocks should heat the water to about 190C before it is pumped back to the surface to drive a turbine that could generate electricity for 3,000 homes. Geothermal Engineering, the company building the £18 million 3 mega-watt demonstration project, hopes it will be the first of many deep geothermal power stations. It estimates that geothermal energy could supply up to a fifth of Britain’s electricity and heat. The company first needs to demonstrate a reliable flow of hot water and has admitted that the project is a “make or break moment for geothermal power in the UK”. After almost a decade of seeking funds, it secured £10.6 million from the European Regional Development Fund, £2.4 million from Cornwall council and £5 million from investors. A geothermal plant has been supplying heat to buildings in Southampton since the 1980s but it uses a much shallower borehole just over a mile deep. By drilling more than twice as deep over the next six months, those behind the Cornish project expect to extract far hotter water.
Times 7th Nov 2018 read more »
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Peter Atherton, an analyst at energy consultancy Cornwall Insight, said: “It’s like tidal. There is a very large energy source there. But can you get it in a way that is ultimately economic and, secondly, what environmental side-effects does it have? “If you can tick those two boxes, there is a big resource there. In the south-west there is a decent geothermal geology.” However, energy expert and author Chris Goodall said: “If this site is successful, hot rocks could provide around 5% of UK electricity and substantial amounts of heat.” Geothermal projects have generated minor earthquakes in the past, but geologists said the risk would depend on the volumes of water and speed with which it is injected. Law said: “Any relative risk of induced seismicity is very well controlled.”
Guardian 6th Nov 2018 read more »