The deepest hole drilled to date - the Kola borehole - went 7.6 miles down. It took 20 years to complete because conventional equipment like mechanical drill bits can’t withstand the conditions at those depths.

Massachusetts-based Quaise Energy has been developing a technology to blast rock with microwaves that could make it easier to drill the deepest holes on Earth.

Speaking at a TEDX event in Boston, the firm’s co-founder Matt Houde said: “The total energy content of the heat stored underground exceeds our annual energy demand as a planet by a factor of a billion.

“Tapping into a fraction of that is more than enough to meet our energy needs for the foreseeable future.”

According to Quaise Energy, if holes could be dug ten miles down, temperatures can be accessed that could be used to economically produce energy everywhere on the planet.

Even deeper holes would allow facilities to heat water to temperatures where it becomes supercritical, a steam-like...