Britain's first geothermal power plant, which will use hot rocks below the surface of the earth to generate heat and energy, has been given the go-ahead in Cornwall.
Local planners approved the scheme at St Day industrial estate, which will involve a 51m high drilling rig boring 5,000m, where the rock temperature is about 170C.
Water will be pumped down, returning as hot water and steam to generate power.
The £40m plant could produce enough energy to heat 20 schools and produce power for 20,000 homes.
Drilling is due to start in 2011, with power production starting in 2013.
Ryan Law, managing director of Geothermal Engineering, said: "Cornwall has very hot granites and we believe it has significant potential.
"It could generate 1GW of electricity, about the same as one big coal-fired power station."
Each plant has a 25-year lifespan before the rocks cool.
The company was awarded £1.5m in funding by the Department of Energy and Climate Change in 2009.