Let’s use the heat beneath our feet to end UK’s energy crisis
HOW THE SYSTEM WOULD WORK
GEOTHERMAL energy is heat from within the subsurface of the earth that can be used for bathing, to heat buildings and to generate electricity.
This is a renewable energy source because heat is continuously produced inside the earth and the thermal energy is stored in rocks and fluids in the earth.
The rock and water in the earth’s crust can reach temperatures of around 370C.
Thermal energy contained in the rocks and fluids can be
GEOTHERMAL energy can help Britain escape soaring global gas prices that have plunged the economy into crisis.
Ecotricity founder Dale Vince, 60, said the heat “right under our feet” can generate electricity and warm households and will be of “enormous value to us in the transition to green energy”.
Dale, who backs the Daily Express Green Britain Needs You crusade, said a quarter of UK homes were in coalfields where water-filled abandoned mines can offer geothermal energy.
This water is heated by geological processes and the temperature remains stable all year round.
The Coal Authority said: “The water in these mines is a low-carbon, sustainable heat source, which can compete with publicsupply gas prices and deliver carbon savings up to 75 per cent.”
The United Downs Deep found from shallow depths right down to several miles below the earth’s surface.
Wells dug into underground reservoirs access the steam and hot water there, which can then be used to drive turbines connected to electricity generators.
A cooling tower crucially rejects waste heat from turbine exhaust steam.
Scientists can then use an injection well to return the fluid to the ground where it percolates through the hot granite to restart the process.
Geothermal Power Project run by Geothermal Engineering (GEL) in Redruth, Cornwall, is our first geothermal power plant.
Almost three years ago two wells, one almost three miles down, were drilled into the granite of the Porthtowan fault zone.
Water at a temperature of 190C (374F) is pumped from the deeper well and fed into a heat exchanger at the surface.
GEL geologist Hazel Farndale says the heat is constantly available and has the smallest surface footprint of any type of energy generation.
She added: “In theory we could get it anywhere in the UK. We just have to drill deep enough. With current drilling technology, it’s best to do this in Cornwall and Devon because we have a granite body that naturally produces heat.”
The Express visited volcanic Iceland where 90 per cent of homes are heated this way.
Agricultural University of Iceland’s greenhouse can be 21C when outside the average temperature is 1C. Horticulturalist Guðríður Helgadóttir said it means “you can grow practically anything” – including bananas.
She added: “This is a way for anyone to see what can be done if you have geothermal energy.” ●●Steph Spyro’s trip to Iceland was hosted by environmental group Green by Iceland