The English city of Stoke-on-Trent aims to harness energy from what is believed to be a 350 million-year-old volcano that still bubbles quietly beneath it.
In a bold move to slash rising fuel costs for homes and businesses, the city council is planning to invest $85m (£52m) in a geothermal district heating network (DHN).
Two miles below the city lies a layer of hot rocks that can heat water to over 105 degrees Celsius, the Stoke Sentinel newspaper reports.
It’s a bit like having a hot water bottle in the ground– Professor Peter Styles, Keele University
Professor Peter Styles, from Keele University, said that the volcano left behind unstable isotopes that are thought to be generating the heat.
"With deep geothermal, you need a particular kind of geology, with rocks that are at a higher temperature than normal," he said. "But as you need to be able to extract the heat through water, you also need permeable rocks."Â
He continued: "It’s a bit like having a hot water bottle in the ground. In this country, there has been more interest in exploiting the higher temperatures seen in granite moorland, but the trouble with that is that it isn’t where people live.
"If you look at industrial cities, such as Stoke-on-Trent, Sheffield or Newcastle-upon-Tyne, they all sit on coalfields, so that would appear a more feasible way of exploiting geothermal."
Stoke-on-Trent joins another English city, Southampton, in combining district heating systems with geothermal energy.
Should plans go ahead, work will begin in 2016. The DHN system would be complete in March 2019.