Historic geothermal energy project now online


Eden Geothermal has switched on its geothermal energy plant at Eden Project in Cornwall. 

Eden Geothermal plant site.
Credit: Eden Geothermal.

The plant will be the UK’s first operational deep geothermal project in 37 years. 

Eden project will use the plant to heat the Rainforest and Mediterranean biomes and the site’s new plant nursery, Growing Point. 

Inside the project 

The initial works for the project started in 2020, with Eden Geothermal splitting the programme into five phases. 

  • Design, preparation and procurement of specialist services. 
  • Site works. 
  • Drilling, completion and testing of the deep well.
  • Installation of a heat main to Eden. 
  • Heat production/supply to Eden, with a greenhouse gas savings calculation. 

The company’s in-house engineering and drilling contractor completed the geothermal well in 2021, which measures 4.9 km in vertical depth. 

Eden Geothermal worked with a water specialist Onsite on the main heat system of the plant, installing a 4 km vacuum-insulated tube that takes in hot water from the well, passes it through a heat exchanger, and then circulates cool water back into the system. 

The heat main is 3.8 km long and around 85C; the hot water feed line and a cool water return line are beneath ground level. 

Heating system diagram. [Credit: Eden Geothermal].
Heating system diagram. [Credit: Eden Geothermal].
What is geothermal energy? 

Geothermal energy is generated in the Earth’s crust, and low-temperature pockets of heat can reach around 150C, though underground rock can hit temperatures of 700-1,300C, according to National Geographic.

Energy stores are easily found in active volcanic and tectonic areas like Italy and Alaska. 

The supply is not standard in stable regions like the UK, but interest in geothermal energy has been present since the 1970s with EGS Energy Ltd’s first ‘Hot Dry Rock’ (HDR) programme, Rosemanowes Quarry new Penryn in Cornwall. 

Though the heating from this new plant will first be used to power local structures around Eden Project, Eden Geothermal anticipates that the resources will expand into more use cases in the future. 

“Geothermal is the sleeping giant of renewables: lying not under our noses, but literally under our feet,” said Sir Tim Smit KBE, co-founder of the Eden Project.

“The Netherlands’ geothermal industry started with heating for greenhouses, and they are now aiming for it to contribute to a quarter of all their heating by 2050.”


Eden Geothermal is a partnership between Eden Project, EGS Energy Ltd, and Bestec (UK) Ltd. 

The European Regional Development Fund and Cornwall Council invested £24 million into the project. 

GCP Infrastructure, an investment trust advised by Gravis Capital Management Ltd., also invested £6.5 million in infrastructure funding into the project. 

Eden Geothermal was approached for further information. 

If you liked this article, we recommend Bids open for £3bn utilities framework. 

Get industry news in 5 minutes!

A daily email that makes industry news enjoyable. It’s completely free.