UK’s first deep geothermal steam at pioneering United Downs project

  • Posted: 01 Jul 2021

The United Downs geothermal project has reached a major milestone in its development, producing geothermal steam which will be captured to generate electricity, keeping it on track to deliver its first power to the grid during 2022.

Final testing continues at the UK’s deepest geothermal well at the United Downs Industrial Estate in Cornwall. Geothermal Engineering Ltd (GEL) and Thrive Renewables' pioneering project is now producing geothermal steam at 175°C which will be captured to deliver approximately 3 MWe of power to the National Grid. United Downs is on track to deliver its first electricity during 2022. The Cornwall Geothermal Distillery Company is in the approval processes to utilise 2.5MW of the hot water the plant is expected to produce.

“As the UK produces increasing amounts of variable renewable energy like wind and solar power, this form of baseload power production plays an essential role in stabilising and securing our power supply. We are delighted to have backed geothermal in the UK at an early stage at United Downs and firmly believe that geothermal energy will form a valuable part of the UK’s future energy mix.” Matthew Clayton, Managing Director, Thrive Renewables

Geothermal Engineering Ltd (GEL), the company behind UK’s first deep geothermal electricity power plant, has announced today that it will be rolling out four new deep geothermal power plants in Cornwall.

“This is an incredibly exciting time for deep geothermal energy in the UK as we transition from oil and gas and tap into this huge renewable power resource. We have proved the technology works at United Downs, we have progressive funding in place, and we now have four additional sites which our experienced team is ready to start work on. Over the next 20 years, our target is to produce in excess of 500 MW of power from geothermal resources making this one of the most significant and reliable baseload power sources in the UK.” Ryan Law, Managing Director, Geothermal Engineering Ltd

To develop each of the future geothermal power plants, two deep wells will be drilled into the granitic rock beneath the site, the deepest of which will reach upwards of 4.5 kilometers. Water is then pumped from the deepest well where temperatures are expected to be approximately 180°C. The steam produced is then fed through a heat exchanger at the surface and water is then re-injected into the ground to pick up more heat from the rocks in a continuous cycle.

The extracted heat will primarily be converted into electricity and supplied to the National Grid, with the residual heat being used as a heat source for homes and industry. The electricity and heat energy produced by this type of low carbon, renewable energy source is continuous (24/7).

“We are excited to support this emerging industry as it continues to take shape in Cornwall, and to realise the benefits it will deliver for the residents of Cornwall. Unlike almost any other form of energy production, geothermal heat energy must be used close to its source. This means that new plants will benefit local communities by attracting new business, jobs and inward investment, as well as offering the potential for delivering local heat networks for residents. Our initial focus, part funded by the governments Heat Network Delivery Unit (HNDU), will be to supply a proposed new housing development of 3,800 homes and commercial buildings at Langarth Garden Village.” Cornwall Council cabinet portfolio holder for the economy Stephen Rushworth