Deep geothermal is when heat from the Earth is used to produce energy, by drilling wells and pumping water. This is also sometimes called an Enhanced Geothermal System (EGS).

The naturally hot granite, here called the Carnmenellis Granite, heats up the water that exists in the rock, which is then pumped up the well. The deepest well, called the production well, will be around 4.5km deep and water at the bottom of the well will be around 190 degrees centigrade.

When the hot water reaches the surface (where it will now be around 175 degrees centigrade) the heat drives a turbine using a heat exchanger. This turbine generates electricity which is fed into the Western Power network. The now cooler water (between 70 and 80 degrees centigrade) travels back down the shorter injection well, which will be around 2.5km deep, to continue the cycle using the approximately 300m wide natural fracture system of the Porthtowan Fault Zone.

If successful this will be the UK’s first geothermal power plant, just outside Redruth in Cornwall.

The University’s research into the United Downs Deep Geothermal Power project is housed in the Sustainable Earth Institute and is funded by Cornwall Council and the European Regional Development Fund (ERDF).

To find out how the University is involved, visit: https://www.plymouth.ac.uk/deep-geothermal

To find out more about the geothermal project itself visit: www.uniteddownsgeothermal.co.uk
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