In partnership with Cornwall-based EGS Energy, The Eden Project in Cornwall planning permission has been granted for a 3-4MW geothermal power plant on the Eden Project site, taking energy from the heat in underground granite rocks.

Geothermal energy is the heat in the rock beneath our feet. Worldwide, natural spas have been enjoyed for millenia, and in active volcanic and tectonic areas, like Italy, hot rocks have been producing power for a hundred years.

Advances in engineering mean that lower temperature resources in geologically stable regions are now usable.

Eden’s proposed geothermal power plant

On a site the size of a football pitch, the geothermal power plant would produce enough power for the Eden Project and around 4,000 houses, plus all the heat we can use, and more.

EGS Energy is part-owned by the team who have already built three engineered geothermal plants in Europe, including one in Landau, Germany.

Engineered geothermal system

The power plant at the north end of our site would be an ‘engineered geothermal system’ (EGS). Here’s how they work:

In construction

  • Two boreholes, each around 25cm wide, are drilled into the rock to a depth of about 4.5km. Water is pumped down one borehole into the natural fractures in the rock to create an engineered heat exchanger between the two boreholes.
  • A heat exchanger is engineered between the two boreholes.

In operation

  • Cold water is injected down one borehole, picks up heat from the rock and is pumped back up to the surface at about 180°C.
  • This hot water runs through a binary cycle turbine to make electricity.

Advantages of geothermal energy

  • Geothermal power is the only renewable energy resource not affected by the weather; it is ‘on’ 24 hours a day, with plants typically running over 90% of the time.
  • The surface area of the plant is the smallest of any power source, and with buildings no higher than 10m, geothermal energy has a low impact on the landscape.
  • Recent research has shown that geothermal energy could provide up to 20% of the UK’s current electricity demand, and a vast amount of heating.

For more information on geothermal energy, please visit the EGS Energy website.