Hot rocks under Hampshire could hold enough energy to heat thousands of homes.
A new geological study has found that Britain has enough accessible underground heat to generate up to 20 per cent of its electricity and provide warmth for millions of central heating systems.
In some areas of the country, rock temperatures can reach as high as 200C (392F), which is enough to generate electricity.
However, in Hampshire the underground heat source does not reach such high temperatures – but could still be used to warm homes and businesses.
Southampton is the only city in Britain that already exploits geothermal energy on a large scale.
A borehole in the car park next to Toys R Us, near Western Esplanade, was drilled in the 1980s.
The system is now run by Southampton City Council and heats many homes and businesses across the city – including The Quays swimming pool, parts of WestQuay shopping centre and the city centre Asda store.
Other “hot spots” around the UK include Cheshire, Weardale, the Lake District, Dorset and Northern Ireland and a £32m geothermal heat and power station is planned for the Eden Project in Cornwall.
Generating geothermal power involves drilling holes until they hit the hot rocks.
Water is then pumped over them at high pressure to open up natural fractures.
The superheated water is pumped back up to the surface, where it can either be used to heat homes or run an electricity generator.
It is estimated that the geothermal industry could be worth £30billion worldwide by 2020, as countries try to find greener energy sources.