The scheme, which ranks as the biggest commercial geothermal projects in the country, could make the Eden Project carbon positive by 2023, providing heat and power for the local area.

A mix of European and private funding will pay for the first phase of the project – drilling one well 4.5km down in the granite and an associated research programme to prove the extent of the resource.

This first well will initially supply a district heating system for Eden’s Biomes, offices and greenhouses. Drilling will start next summer.

It will pave the way for the second phase – another 4.5km well and an electricity plant.

The Eden Project has teamed up with BESTEC, a German specialist geothermal developer and drilling advisor. and local Cornish geothermal specialist EGS Energy to deliver the ambitious test project.

Eden co-founder Sir Tim Smit said today that securing funds and thereby the chance to spark an energy revolution amounts to the biggest leap forward for Eden since it opened in a former clay quarry near St Austell in 2001.

“Geothermal will be a game-changer for Eden, Cornwall and the UK.

“The heat will be used for the Biomes, to grow food, as well as helping support the development of our long-awaited hotel.

“Once up and running, our plant will provide more than enough renewable electricity and heat for the whole site, as well as for the local area. We will be drilling for good energy rather than bad.”