Hot rocks hold hope for West economy

Drilling will start this week at what could become the UK’s first “hot rocks” deep geothermal electricity plant.

Two wells up to 4.5 kilometres deep will be drilled through granite near St Day in Cornwall.

Water will be pumped from the deepest well at a temperature of about 190C, fed through a heat exchanger at the surface and re-injected into the ground to pick up more heat in a continuous cycle.

The extracted heat will be converted into electricity and supplied to the National Grid.

The developers, Geothermal Engineering Ltd, said the aim was to demonstrate the potential of geothermal technology to produce electricity and renewable heat in the UK.

The plant at the United Downs industrial estate is thought to have the potential to supply up to 3MW of electricity, enough to power 3,000 homes.

Geothermal technology is described as a “continuous” energy source because it does not suffer from peaks and troughs.

Developers hope the technology used at the facility could be used in other locations in Cornwall and Devon.

South West MEP Molly Scott Cato said: “The beginning of hot rock geothermal energy gives me a warm glow. This is fantastic news for Cornwall. With its rich mix of renewable energy resources, the region has the potential to be the hub of a future Western powerhouse in renewable energy generation.

“This could be a major export for Cornwall, creating thousands of new jobs and boosting the local economy.”

The £18 million project has received £10.6 million funding from the EU’s European Regional Development Fund, £2.4 million from Cornwall Council and £5 million from private investors.

Dr Ryan Law, managing director of Geothermal Engineering, said geothermal resources have the potential to deliver up to 20% of the UK’s electricity and heat energy needs.