The US Energy Department has invested $2million (£1.3m) into five clean energy projects.

The projects will explore the potential of geothermal energy.

They are the first part of the multiphase ‘Frontier Observatory for Research in Geothermal Energy’ (FORGE) effort.

The laboratory will look into enhanced geothermal systems (EGS) and could unlock clean energy with the potential to supply power to up to 100 million homes in the US.

Under Secretary for Science and Energy Lynn Orr said: “Through these kinds of critical investments in renewable energy, the Department is helping develop cost-effective technologies for engineering geothermal systems that supply affordable, zero-carbon energy to millions of American homes and businesses.”

EGS are engineered geothermal reservoirs, which are created beneath the surface of the earth, where there is hot rock but not many pathways for the fluid to flow through.

The EGS development pathways are created and expanded to allow fluid to carry more heat to the surface and create electricity.

This could lead to more than 100GW of extra electricity capacity in the US.

Ms Orr added: “Enhanced geothermal systems could represent the next frontier of renewable energy and hold the potential to diversify the nation’s energy portfolio while reducing greenhouse gas emissions into the atmosphere.”

The projects will take place in in California, Idaho, Nevada, Oregon and Utah.