Installation of heat main to supply Eden Project with geothermal heat completed

Installation of the 3.8km heat main which will supply Eden Project’s Biomes, new greenhouses and other buildings with renewable heat from our geothermal well has now been successfully completed. The new heat main consists of two 150mm (6”) steel pipes – a flow and a return – each encapsulated in a thick layer of insulation to a total diameter of 280mm and linking the deep geothermal borehole with the Eden Energy Centre.

All but a very short stretch of the pipe has been installed below ground, so you won’t see it if you visit the Eden Project. But our contractors, OnSite Pipelines (part of South Staffordshire Plc), made this short film during the works, offering a great birds-eye view of the installation.

The full geothermal heat network, which is expected to be operational from early 2023, will work as a series of closed loops:

In the first loop, hot water from deep underground will be brought to the surface of our geothermal well using a coaxial circulation system (currently being manufactured) and heat will be extracted from it using a heat exchanger. The newly-cooled water will then be returned underground to be reheated, in a continuous circulation system.

The new heat main will form the second closed loop, collecting heat from the heat exchanger at the Eden Geothermal well site and transporting it to the Eden energy centre and new nursery on the main Eden Project site.

There, two further heat exchangers will extract the heat for use in the two heating circuits supplying the Biomes / main Eden Project site and the new plant nursery, with the cooled water in the heat main being returned to the Eden Geothermal site for reheating.