Image from Flickr creative commons via Franziska Lux
Fracking – or hydraulic fracturing – in its simplest terms is the process of extracting natural gas from layers of rock deep within the Earth. It is a relatively new process in the world of fossil fuels and has allowed gas extraction at depths that were previously unreachable.
It is estimated that at least 60 per cent of all new oil and gas wells worldwide were being hydraulically fractured. Most commonly, the process involves drilling a horizontal hole into the rock layer – sometimes it is also done vertically. A high pressure mix of water, sand and chemicals is then injected into the rock, allowing the gas inside to flow out.
Its first experimental use was in the late 1940s and fracking was first commercially successful in 1949. By 2012, 2.5 million hydraulic fracturing jobs have been performed on oil and gas wells worldwide.
But, it is not as simple as that. It is a controversial process. Much of the water used is collected from the well and processed but there are concerns carcinogenic chemicals can escape and find their way into drinking water. It has also been reported by NBC News in the US that tap water becomes flammable as a result of nearby fracking.
Tim Yeo MP, chair of the energy select committee, has refuted some of these claims. He told the BBC in 2011 that problems experienced in the States could be overcome with tight regulation and practice.
He said: “We can’t see any evidence that UK water supplies might be at risk from shale gas – if it is done properly.”
Perhaps predictably, the industry itself also denies that shale gas is unsafe and similarly declares incidents of pollution to be examples of bad practice, rather than of a risky technique.
Some will also claim that the gas extracted through fracking presents a danger to the environment. As a cheaper substitute for renewable energy sources, it is easy to see why certain companies with more of an eye on their wallets than on the planet would go down this line.
However, emissions from natural gas are a small proportion of those emitted from other fossil fuels like coal and oil.
An imminent report by the British Geological Survey is expected to announce that shale gas deposits are far larger than previously predicted. Experts say we could be sitting on enough gas reserves to supply the nation for more than a century.
It has also been suggested that two small earthquakes in Blackpool in 2011 (measuring 1.5 and 2.2 on the Richter scale) were a result of nearby fracking operations. Drilling was suspended while an investigation took place. When the company in charge of the project, Cuadrilla, returned to a second site in Fylde in May 2013 they were greeted by hundreds of protestors.
Protestor Max Walton, told the Blackpool Gazette: “Fracking will not bring gas bills down, will damage our countryside, and will not provide long term jobs to help counter unemployment… Camp Frack Two [the name of the protest] is designed to help local people learn more about fracking.”
Talking about its potential to cause earthquakes, Professor Ernie Rutter from the University of Manchester said: “It’s always recognised as a potential hazard of the technique… But they’re unlikely to be felt by many people and very unlikely to cause any damage.”
A conclusion, though, seems far from close. Professor Richard Davies from Durham University’s Energy Institute led an investigation into the process of fracking which concluded in April of this year.
It found the tremors caused were the equivalent of someone “jumping off a ladder” and that is was it is “extremely unlikely that any of us will ever be able to feel an earthquake caused by fracking”.
Prof Davies said: “In almost all cases, the seismic events caused by hydraulic fracturing have been undetectable other than by geoscientists. It is also low compared to other man-made triggers… whereas, most fracking-related events release a negligible amount of energy roughly equivalent to someone jumping off a ladder onto the floor.”
The Durham University team collated data on all earthquakes caused by human industrial activity since 1929. The largest tremor due to the fracking process was at Horn River Basin in Canada in 2011. It measured 3.8 in magnitude, something they said would feel like no more than a shudder to most people.
Earthquakes caused by activities such as mining can measure as high as 5.6 on the Richter scale, while reservoir filling can measure up to 7.9.