Geothermal power plant in Cornwall secures funding

Geothermal Engineering has finalised the design of its plant, which it hopes will be generating power by 2015.

Exploration of Cornwall’s geothermal potential dates back to the 1970s with the ‘Hot Dry Rock’ research project, which aimed to characterise the mechanical properties of the underlying granite.

Data from this project has formed the basis of Geothermal Engineering’s proposals, which will include three wells 4.5km deep and a binary power plant capable of generating up to 300MW.

The injector well will fire cold water down to the rocks to migrate through natural ‘heat reservoirs’ in the granite towards two producer wells 800m apart, which will take hot water to the surface for electricity generation.

‘The crux of this whole deep thermal business is that reservoir and how it functions,’ said Ryan Law, managing director of Geothermal Engineering and a former geotechnical engineer for Arup on the original Hot Rock Dry project.

‘This is a big fault zone where the granite has been messed around and turned into almost a rubble, so there are very small openings within the granite, almost natural fissures or faults, through which the water can move. It’s a big heat exchanger effectively and all you’re trying to do is get the water to pick up as much heat as possible between the injector and producers.’