Enough gas has been discovered beneath the soils of Lancashire to power the UK for 66 years, according to Cuadrilla Resources, but will it ever be exploited?
The mining company's survey claims to have found up to 5.66 trillion cubic metres of gas in the Bowland Shale area near Blackpool, the extraction of which could directly generate 1,700 jobs in the area, with more ancillary jobs resulting.
The company's chief executive Mark Miller said that between 400 and 800 wells could be dug.
This amount of gas is considerably larger than the British Geological Survey's previous estimate of the UK's total onshore shale gas resources - up to 150 billion cubic metres.
Whatever the true amount, which has yet to be independently verified, much of this gas may not be feasibly recoverable, and environmentalists have been quick to point out the problems associated with the technology used to extract it.
This is a process known as a hydraulic fracturing, or fracking, in which huge amounts of water, sand and chemicals must be injected at high pressure into deep wells to force the gas out.
In Lancashire, Cuadrilla has suspended fracking operations pending the results of investigations to find whether it caused two minor earthquakes in June.
The research is being conducted by looking specifically at the geological and seismic properties of the rock strata and shale in and around Poulton-le-Fylde, and any linkages between the recent seismic tremors and hydraulic fracturing operations in the area.
The Department of Energy and Climate Change is due to receive the results of the study shortly, but the British Geological Society says that it is well known that injections of water or other fluids during processes such as oil extraction, geothermal engineering and shale gas production can result in earthquake activity.
Typically, the earthquakes are too small to be felt; however, there are a number of examples of larger earthquakes occurring.
The Hot Dry Rock Geothermal energy research project at Rosemanowes, Cornwall resulted in many thousands of induced earthquakes. However, only one, with a magnitude of 2.0, was felt.
Environmental cost of fracking
Climate camp protestors have begun a camp at Hesketh Banks near Preston, one of three sites where exploratory drilling is continuing, and cite several environmental concerns that led France to become the first country to ban the process, back in July.
Local residents are anxious that drilling will not result in episodes like that which occurred in June 2010 in Clearfield County, Pennsylvania, when a geyser of natural salt water, mud and chemicals shot out of a well called Punxsutawney Hunting Club 36, 75 feet into the air for a period of 16 hours.
In North Texas, fracking is resulting in a shortage of sand, which has to be mined and transported to the site by the gas producer EOG Resources. This has attracted local opposition because of the air and noise pollution.
Throughout North America, the increase in fracking has driven up demand and prices for the sand. "There's been a sand shortage in the U.S.," according to Mark Papa, the chief executive officer of oil and gas producer EOG Resources. "And so those who have sand or have access to sand can pretty much charge what they want for that sand."
In 2009 in the US, the process used 6.5 million tons, a figure expected to have doubled in 2010, when statistics become available.
Elsewhere, aquifer water has been contaminated, and in New York methane has entered domestic water supplies.
Substantial amounts of water are required. Evidence given by the Tyndall Centre to the Energy and Climate Change Committee suggests that "to sustain production levels [of shale gas] equivalent to 10% of UK gas consumption in 2008 would require around 2,500-3,000 horizontal wells spread over some 140-400km2 and some 27 to 113 million tonnes of water".
For all of these reasons WWF-UK is opposed to the production of shale gas in the UK.
Shale gas and climate change
There is also concern about the climate impact of fracking. This, although yet unclear, is certainly higher than that for natural gas which, when extracted conventionally, has between two-thirds and one half the global warming potential of coal.
Non-peer-reviewed reports from the US quoted by the Tyndall Centre in the above paper put the extra amount of CO2 at 0.14-1.63tonnes CO2/TJ of gas energy extracted.
A more recent study by Cornell University has found that shale gas can have the same or greater impact as coal, especially when the impact is measured over two decades.
The paper concludes: "Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon and is comparable when compared over 100 years."
The paper looks at the impact of the fact that between 3.6% and 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the well's lifetime.
The researchers add that "the GHG footprint of shale gas approaches or exceeds coal even when used to generate electricity".
The paper does not include in its life cycle analysis the global warming impact of the mining and transportation of the sand, chemicals and water used in the fracking process, and so the overall impact may in fact be greater. But no study has yet been undertaken that does this.
The position of Connie Hedegaard, the European Commissioner for Climate Action, given in July, is that "it is too early to draw any firm conclusions regarding the climate and environmental impacts of possible future shale gas exploitation in Europe".
She said that the environmental and commercial viabilities of potential shale gas sources still need to be established, and that the Commission is monitoring the situation in order to minimise potential environmental and climate impacts of shale gas exploration and production.
The government's wait-and-see approach
The British government is also adopting a neutral position. In answer to a Parliamentary Question in July from Green MP Caroline Lucas, Charles Hendry, minister for energy and climate change, said that he had "made no assessment of the greenhouse gas emissions of shale gas related extraction: emissions from shale gas extraction processes will be determined by the design and conditions of a particular development and no development has been proposed for the UK."
Answering another question from Conservative MP Laurence Robertson, Hendry said the government will "continue to encourage the energy industry to maximise indigenous oil and gas production and infrastructure opportunities".
In a separate debate on energy, Hendry's opinion was that the fracking fluid "is 99% water and the majority of the remainder is an inert soapy-type compound", and that he was satisfied with the environmental controls that were in place to cover the methane's extraction.
The Energy and Climate Change Committee issued the results of their investigations into shale gas in May.
MPs said that the technique does not pose a direct risk to underground water aquifers, provided that the well to be hydraulically fractured is constructed properly.
Their report also expressed satisfaction that existing environmental regulations and enforcement would prevent leaks of methane from wells or pipelines, based on advice from the Environment Agency.
But MPs did express concern that a concentration on shale gas could "divert investment away from renewable technologies like solar, wind, wave or tidal power".
They concluded that although it has less global warming impact than coal, shale gas "will not be sufficient to meet long term emissions reductions targets and avoid the worst effects of global climate disruption".
Given that Chris Huhne signalled this week that he wants to minimise the construction of more gas-burning power stations unless they also include carbon capture and storage, then this may, at least, limit the domestic market for shale gas, even if Cuadrilla overcomes local opposition and receives planning and environmental consents for further drilling.