The deepest and hottest geothermal wells in the world have been completed after 10 months of drilling at United Downs in the southwest of England near Falmouth. The $22 million wells are 3.1 miles deep and 383º F /195º C at the bottom.
Ryan Law, managing director of Geothermal Engineering Limited, tells Good News Network the initial water flow tests at the site suggest the project will be capable of producing the UK’s first geothermal electricity and sustainable heat.
“We are delighted to have completed the drilling of these technically challenging wells,” says Law. “Reaching our target at the Porthtowan Fault Zone, at such a depth, was a fantastic achievement in geological and engineering terms and the initial flow tests are very exciting for unlocking the potential of the granite in Cornwall.
“What we are doing…..is vitally important for the whole geothermal energy sector. All eyes were on us. There has been an enormous amount of interest in this site from all over Europe so it was very important that we drilled these two wells successfully. The potential is enormous. We have identified at least another 20 sites in Cornwall so, planning permission permitting, our rig will be seen around Cornwall again in the near future.”
Scientists and researchers from 27 universities have been involved in the project during the drilling phase of the project. Dr. Law said further tests will be required over the next three to four months before the actual geothermal power plant is built on top.
The drilling rig used to bore the J shaped wells is a massive beast, but GEL says the power plant that will be constructed on top of the wells will be no bigger than three 2-car garages. The company plans to begin producing geothermal electricity — up to 3 megawatts — by next spring.
The J shape of the well is designed to intercept a geological structure known as the Porthtowan Fault, which makes it possible for water to continuously circulate through the hot rock from the injection well and back into the production well. As the water moves through the rock, it picks up heat which can be extracted and converted into electricity at the surface.
Geothermal technology has one important characteristic that many sources of renewable energy lack. It operates 24 hours a day and is not dependent on sunshine or wind speeds to make electricity. The United Downs project is intended to demonstrate the feasibility of geothermal technology in the UK and prove it can play an important role in the future of renewable energy.