The untapped reservoir of hot water beneath UK cities could provide green energy for millions of homes.
A pilot scheme in Cardiff shows that it is possible to heat buildings using groundwater beneath the Earth’s surface. If this technology was rolled out across the UK it could provide green energy for millions of homes and small businesses.
The UK has set an ambitious target of reducing its net greenhouse gas emissions to zero by 2050. The solution may be lying right under our feet; there is potentially enough geothermal energy under the Earth’s crust to provide for all our power needs for billions of years, all we need do is harness it.
If you were to dig a big hole straight down into the Earth, you would notice the temperature increasing the deeper you go. That’s because the inside of the Earth is full of heat – emanating from the planet’s core, and the radioactive decay of uranium, thorium and potassium in certain types of rocks. Unfortunately, most of this heat is inaccessible; but tapping just a fraction of it would make a substantial contribution to reducing greenhouse gas emissions.
One option is to drill deep down into rocks to access hot waters directly. In most regions of the UK this would be madness, as the drilling costs would be astronomical. However in the south west of England, where the crust contains large amounts of heat producing granites, it may be feasible, and a geothermal power plant is currently under development at United Downs.
However the risks from drilling deep boreholes into the Earth’s crust are not yet fully understood, with some fearing the impacts on seismic activity. BGS scientists in Cardiff believe that a more promising route lies in accessing shallow groundwater just meters beneath the ground.
To read more about this, check out the Planet Earth website.