The Eden Project, which opened in 2001, is a visitor attraction located in a reclaimed Kaolinite pit in Cornwall, England. The complex comprises a number of transparent domes emulating natural biomes housing plant species from around the world. Initially the plant would be used to supply the Eden Project, but could potentially feed spare carbon-neutral electricity into the National Grid.
Cornwall’s “hot rocks”
Eden and its commercial partner, EGS Energy, believe this is the first in a series of projects that could lead to Cornwall's “hot rocks” generating up to one-tenth of the UK's electricity. Matt Hastings, Eden's energy manager, said: “It's a massively exciting project - a way of making sure Eden has a source of green power but also of feeding heat and power into the local community and into the National Grid. We will only need a quarter or a fifth of the electricity that will be generated. Cornwall leads the way in wind and wave energy technology. Now we're trying to do the same in geothermal power.”
Cornwall is considered to be an ideal location for geothermal technology because its granite outcrops are relatively close (around 4 km) to the surface. Roy Baria, technical director of EGS Energy, explains that: “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.”
If planning permission is granted, two boreholes of between 3 km and 4 km deep will be drilled in the same disused clay quarry as the centre. Water will then be pumped into an injection hole and allowed to percolate through the hot rocks to heat up to approximately 150ºC. It will then be pumped back out through the second hole and passed through a heat exchanger to generate electricity. Any excess heat in the water will be used to heat local buildings, hopefully not just at Eden but in surrounding areas. Spare heat could also be used by Eden for growing exotic fruit and vegetables out of season or possibly to heat a spa.
It is estimated that the plant, which could be ready by 2012, could generate enough electricity to supply the equivalent of almost 5,000 homes. Tim Smit, chief executive of the Eden Project, said it was a “pioneering” scheme and added: “Powering the Eden Project site from a renewable source of energy is clearly a priority for us.”
The government is watching the plans closely, with Ed Miliband, the secretary of state for energy and climate change, present at the launch of the project in London.
