Geothermal energy production in Cornwall- Is it viable?

Today marks the start of drilling for what may become the first deep geothermal power plant in the UK. Falmouth based firm Geothermal Engineering are drilling two wells, 2.8 miles (4.5km) and 1.5 miles (2.5km), into granite near Redruth, Cornwall.

Cold water will be pumped down to the hot rocks where the temperature is up to 200C (390F). Hot water will be brought to the surface. Steam from the heated water will drive turbines producing electricity. If this pilot project is successful it could pave the way for similar power production in the UK.

Professor Joe Quarini from the department of Mechanical Engineering shared his thoughts on the project:

Professor Joe Quarini talks to Jon Kay from the BBC

“This is a good and exciting project from an engineering perspective. Not only will it bring jobs and expertise to Cornwall, but we’re going to learn a lot about engineering as the work progresses. We’ve seen similar, but ‘easier’ projects work successfully in New Zealand, Iceland and Italy. There are some technical questions that will be answered during this pilot, like, whether there are significant fouling issues associated with leaching out soluble minerals from the underground structures, what proportion of the water pumped into the ground actually comes back and whether and at what rate the heat deposits are depleted.

The answer to these questions will dictate the long-term viability of geothermal energy production in the UK. Cornwall is unique, it has heat-producing granite rocks with the highest energy density in the UK. In terms of absolute sums, electrical power production from geothermal is likely to be a small proportion of the Nation’s needs; it best location will be Cornwall. That said, Engineering is a global discipline, so it’s great for our young engineers to get the opportunity to see projects like this in action. We know that young people are really interested in green energy and sustainability so hopefully this will get more young people interested in Engineering as a subject.

Whilst the project excites me in terms of Engineering, I’m less confident about the long-term economic viability of geothermal energy in the UK. When the engineering costs are accounted for, geothermal energy isn’t the cheapest source of power, but if we’re serious about decarbonising our economy then it’s a choice that we, as a society, can make. That’s where funders like the EU and the Government come in to help subsidise projects like this one. My worry is that when those sources of funding aren’t available this won’t be a very attractive prospect to private investors. I’d love to be proved wrong on this though!”

Hear Joe in conversation on BBC Radio 4’s Today Programme at 1:21