The United Kingdom has more shale gas than previously thought, a new study has found.
An assessment by the British Geological Survey (BGS) released yesterday shows that gas trapped in deep-lying shale rock formations could amount to as much as 2,281 trillion cubic feet (tcf) in central Britain alone.
But it is the median estimate of 1,329 tcf that was leaked to the press before the release of the report that is regarded as the most credible.
The BGS report assesses the shale potential of the Bowland-Hodder study area that covers many of England's northern cities, including Manchester, Liverpool and Leeds.
The new assessment is significantly higher than previous estimates. The BGS makes no predictions on how much of these resources are recoverable, however.
Resources are always greater than the amount of gas that can ultimately be produced, and recovery rates depend on a variety of factors. For now, the lack of exploratory drilling means that too little is known about the geology in which the gas is contained, making an estimation of recoverable reserves impossible.
"In time, the drilling and testing of new wells will give an understanding of achievable, sustained production rates," the report reads. "These, combined with other non-geological factors such as gas price, operating costs and the scale of development agreed by the local planning system, will allow estimates of the UK's shale gas reserves to be made."
Shale gas is brought to the surface after hydraulic fracturing, or fracking, has flooded the rock formations with a mix of water and chemicals. This production method has drawn heavy criticism from environmentalists, who fear the risk of earthquakes, water contamination and the escape of methane gas into the atmosphere.
In the United States and Canada, shale gas is produced extensively, and has brought gas prices crashing down. The UK has to import much of its gas, paying hefty premiums particularly for liquefied natural gas (LNG) imports. This has prompted the government to take a close look at the UK's shale gas potential, and has led the chancellor, George Osborne, to call for a "dash for gas".
Analysts have criticised the chancellor's enthusiasm for shale gas, as "it ignores the very real barriers to shale gas development in the UK and Europe more generally", according to Paul Stevens, a senior research fellow at Chatham House.
Apart from a high clay content in British soil, the UK's population density is higher than in the US, where a highly developed oilfield services industry and extensive infrastructure facilitated the shale revolution. The tax breaks available to US shale producers are absent in the UK, notes Mr Stevens.
So far, Cuadrilla is the only company drilling for shale in the UK.