In Cornwall, the deepest well yet drilled in Britain now penetrates 5.1km into the earth’s crust, burrowing into fiery depths where the temperatures can reach 195C.
This – literally – groundbreaking well will soon be the UK’s first genuine functional geothermal power station.
Water will be pumped down into the Porthtowan fault, a geological formation through which it can be circulated, flowing in a continuous cycle. This water is heated up by the hot rocks, and pumped back to the surface where – as steam – it powers turbines.
The final power station will be small, discreet, produce no greenhouse gases, and be very low-cost to maintain. It will produce three megawatts of electricity, continuously, which is the average energy consumption of around 6,000 homes; providing “baseload” energy to the national grid.
If the hot water condensed after passing through the turbines is well used, through a combined heat-and-power scheme, it can heat buildings, showers, and even heated greenhouses. This could massively reduce fossil fuel usage. Indeed, less-deep geothermal wells, and combined heat-and-power from nuclear (or combustion power) would be a big step forward.
That will require a higher level of integration of heating systems, with significant upfront investment – but is necessary, and would reduce costs overall.
This geothermal well is important as a test project. Drilling on the well was started in November last year, and completed this September. This makes the timeframe for construction of the whole power station likely under a year and a half – significantly shorter than many power stations.
On Monday 14 October, it was announced that a second geothermal power station will be joining this first, also in Cornwall – built in the Eden project. The initial £16.8 million funding for this was 60% from the EU, 40% from “institutional investors” and 10% from Cornwall council.
Previous geothermal projects have been shelved when government funding has been pulled. Privately owned projects, as many of them are, siphon a lot of money away as direct profit, into the pockets of the CEOs and shareholders.
Billions of pounds should be poured into construction of publicly owned renewables, including geothermal.