THE first geothermal heating plant to launch in the country for almost four decades wants to increase the number of 5km underground wells it was previously allowed from two to six on land at the Eden Project.

Eden Geothermal says the changes to a previously approved planning application offer “a significant benefit in terms of increasing the renewable energy generated on site.”

The company also wants to make other changes to its agreed plans to allow for an increase in generation capacity to 15MW. The key changes include increasing the size of an air cooled condenser bank, reconfiguration of site buildings and the installation of two substations, rather than the one previously agreed with Cornwall Council. The plant’s water storage lagoon would be decreased in size if the changes are agreed.

Reaching around 5km, or three miles, below the Earth’s surface, the current geothermal well taps into water temperatures of up to 200C to provide heating to Eden’s greenhouses and rainforest biome.

Members of the public who live near the Eden Project can discuss the proposed changes with the Eden Geothermal team when their altered plans are displayed tomorrow (Wednesday, October 28) between 3pm and 7pm at nearby Trethurgy Village Hall. There will be another meeting on Friday, November 6 between 3pm to 6pm.

The current well at Eden Geothermal has a vertical depth of just over three miles. A second similarly sized well was also approved in December 2010, but has yet to be drilled. The project now wants to drill four more wells in a bid to increase capacity “without the need to extend beyond the approved boundary or substantially alter what has already been approved”.

A supporting report by Gilly Slater, on behalf of SLR Consulting Limited, states: “The increase in the installed capacity of the geothermal facility necessitates a larger air cooled condenser bank to cool the geothermal fluid from the additional wells. The reconfiguration of the site buildings and the installation of the two substations slightly increases the overall floorspace of buildings by 59sqm.

“The surface area of the site remains unchanged, such that the proposed amendments will not result in any impacts to the Tree Preservation Order area or the existing drainage system and strategy.

“As there is extant permission for the drilling of an additional deep geothermal well at the site, due to significant improvements in drilling technology in recent years, it is not expected that the drilling of the additional four wells would result in the drill rig being on site for any longer than already approved, such that all noise levels and visual impacts associated with the drilling phase will not alter from the approved.”

The nearest residential property lies 60 metres from the site’s eastern boundary, while the nearest settlement is Trethurgy, which sits 340 metres to the west.

Cornwall Council’s landscape team are supportive of Eden Geothermal’s mitigation of likely effects of the proposals on the site itself and upon its wider landscape context. They stated: “It should be noted that the development / construction phase of the project may involve disturbance through other environmental factors (dust, noise, etc) which lay outside of the scope of this consultation and report”.

The application, PA26/05364, has a determination date of Wednesday, November 18.