The first geothermal power plant in the UK is being planned for development in Cornwall using hot rocks. The Cornwall Geothermal Project will be constructed by EGS Energy, a renewable power company focused on engineered geothermal power and will use granite outcrops near the earth’s surface for the heat to generate electricity.

This geothermal power plant would be used to generate power for the Eden Project in Cornwall but will eventually feed power into the National Grid.

The process of generating electricity from the heat of the hot rocks found under the earth in Cornwall is undertaken by first drilling bore holes down 3 – 4km to the granite. Water is then pumped down into injection holes and sent through the hot rocks which heats it to around 150 degrees Celsius by the time it is returned to the surface. The hot water is then converted to electricity via a heat exchanger.

If the project gains planning permission the aim is to have the power plant ready to begin producing electricity by 2012.

Estimations done by EGS Energy have indicated that the resource of the Cornwall area has the potential for supplying 10% of the UK’s electricity for 200 years.

There is already a geothermal project in Southampton that supplies heated water to a number of customers but this will be the first project that converts that heated water into electricity.

Roy Baria, technical director of EGS Energy and formerly deputy project director at the Rosemanowes “Hot Rocks” project in Cornwall said “With the geology in the vicinity of the Eden Project being ideal for creating our power plant and its reservoir, we would not only expect to be able to supply virtually all of the Eden Project’s power and heat requirements but generate surplus power that could be fed into the grid to help meet the government’s CO2 reduction and renewable generation targets.”