Deep Geothermal Electricity

By Nicky Davis

Despite how frozen the ground has appeared lately, under the surface it is hot. Much of the reason for this is the energy released by radioactivity which occurs naturally in the rocks, from isotopes generated 4.6 billion years ago when the Earth was formed and their radioactive decay products, some of which are also radioactive.

All we need to generate electricity is: a source of energy to use to turn water into steam, to turn turbines, to produce electricity by rotating a magnet within a coil of wire to produce a voltage. This is essentially how most power stations work, although the source of energy varies. The photograph is of the power station at Rugeley, which burns coal as an energy source.

So why not use heat from underground as a source of energy to produce electricity? This is the view of geologist Ryan Law from Geothermal Engineering.

This method would not be so applicable in Staffordshire, as it works best in areas with rocks such as granite that contain high levels of natural radioactivity. There are obstacles to be overcome, such as the complexity and expense of drilling deep into the ground and the disruption even minor tremors can cause. Nevertheless Geothermal Engineering plans to do this near Redruth in Cornwall, with the hope of commercial operation by 2014.

The advantage of the method is that it is carbon free and produces electricity continuously. It will be interesting to see how the Cornish project works out.

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