The geothermal plant would generate heat and electricity.
Plans are being drafted for a geothermal energy plant in Cornwall to provide electricity and heat for homes and businesses.
The sustainable energy plant would be based in Redruth and provide 55MW annually for local use and 10MW for the national grid.
Geothermal systems use the Earth's natural heat to generate electricity.
Geothermal Engineering Ltd (GEL) is due to exhibit plans in October and submit the proposals in December.
Drilled into ground
If approved it is estimated the plant would provide heat and electricity for businesses and community buildings in a city the size of Truro.
Its contribution to the national grid would be the equivalent of providing heating and electricity for 30,000 homes.
Wells 5km deep would be drilled into the ground where temperatures reach 170C (338F).
Water would be pumped down into the rock where it is naturally heated, before being pumped back to the surface as hot water or steam.
The heated water would power turbines, generating electricity and heat.
Managing director of GEL Ryan Law said: "Our vision is to provide renewable heat and power at minimal environmental cost.
"There is significant potential for geothermal energy to encourage investment into the region."
The plans will be submitted to Cornwall Council in December and, if approved, it is estimated initial drilling would start next year with the plant operational by 2013.
It is estimated the plant would cost £40m to build.
Geothermal energy is already used in Australia, Iceland and America as an alternative to fossil fuel.