One of the energy firms hoping to exploit the UK’s resources of shale gas says it may be sitting on significantly more gas than previously thought.
UK firm IGas says there may be up to 170 trillion cubic feet (4,810 cubic km) of gas in the areas it is licensed to explore in northern England.
But it remains unclear how much of the gas will be economically extractable.
Shale gas is extracted by fracking – pumping water, chemicals and sand at high pressure into rock to release gas.
Critics argue that the process may cause earth tremors and want investment in green energy.
Fracking has revolutionised the US energy market and the energy industry has hopes for a similar transformation in the UK.
IGas is one of the companies granted a licence by UK authorities to explore parts of the country believed to contain large resources of shale gas.
The company’s licences cover an area of 300 sq miles across Cheshire.
It had previously said it had about nine trillion cubic feet of shale gas. It now estimates that the volume of “gas initially in place” could range from 15.1 trillion cubic feet to 172.3 trillion cubic feet, the higher figure being nearly 20 times higher than the previous estimate.
The UK’s annual gas consumption is currently about 3 trillion cubic feet.
Video - UK shale gas reserves may be 'bigger than first thought'