Shale gas: energy saviour or environmental disaster?

But the method of reaching this hard-to-extract resource has prompted accusations it damages health and the ecology, prompting a US Government investigation into whether the process is safe.

It has long been known that enormous pools of natural gas are locked in underground rock formations, particularly shale. But with plentiful supplies of oil, gas and coal available it was largely ignored. However, dire warnings about the limited remaining stocks of these fuels and the environmental harm they cause have prompted a rethink.

The shale gas supplies are estimated to be so large that they could satisfy America’s gas needs for the next century. The shale gas boom in America, where it is already providing 10% of the nation’s gas, has led to exploration in China, India, Australia, Indonesia and Europe. The first exploratory well was dug in the UK at the start of this year.

There is enough existing conventional gas to last the world for another 60 years, says the International Energy Agency. But by adding in “unconventional” sources, such as shale gas, reserves could last another 250 years, although it stresses this estimate is very uncertain.

As natural gas has only half the carbon emissions of coal, shale gas could also help in the fight against climate change, by providing a bridge between polluting oil and gas and new renewable energy sources.

Environmental worries

But there are growing concerns that developing these gas reservoirs may cause serious environmental harm. That is because the shale gas boom has been enabled by a technique called hydraulic fracturing, or “fracking”. It involves pumping huge volumes of water, sand and chemicals at high pressures deep underground to break up rock formations and allow the gas to escape into wells from where it can be piped to the surface. Most of the brew of water and cocktails used to extract the gas stays far beneath the earth, however, with uncertain long-term consequences. Campaigners are calling for the technique to be halted until further research can be carried out. 

In America, where there are now around 35,000 shale gas wells, there are growing protests over fracking. There have been cases of blowouts and gas leaks while hundreds of residents living close to gas wells in Texas, Wyoming and Pennsylvania have complained the cocktail of chemicals used in the drilling process has polluted their groundwater, causing many illnesses, while farmers blame poisoned well water for deaths and deformities among their cattle.

Energy companies deny that fracking is to blame for contaminated water. The technique has been used for decades but has only become widespread recently since shale gas has been seen as a viable alternative to oil and coal. The drilling companies are exempt from legislation on clean water so can keep the chemicals they use a closely guarded secret.

Action being taken

The US Congress has responded by directing the Environmental Protection Agency (EPA) to study the effects of fracking. In February, the EPA issued a draft plan outlining how it will investigate the issue, including proposals to take water samples from sites before, during and after fracking has taken place. The EPA expects to publish its initial report by the end of 2012, with a further in-depth study due two years later.

But some cities have pre-empted the EPA investigation and taken unilateral action. The cities of Pittsburgh, Pennsylvania and Buffalo in New York have already chosen to ban fracking in their regions. Others have called for a moratorium on the process until more is known about its potential consequences. 
Investors have also raised concerns. In 2010, 12 energy firms, including Exxon Mobil, faced shareholder resolutions at their annual meetings calling for them to introduce better safeguards against environmental damage caused by fracking.

Some critics argue the rush to develop shale gas is diverting attention away from the need to find new, clean energy supplies. In January, the Tyndall Centre – a respected climate thinktank – published a report warning of the dangers of developing shale gas. The gas would not be used to substitute coal but, instead, is likely to be used as well as coal to meet the growing demand for energy, it said. Without a tough cap on greenhouse gases, shale gas exploitation could result in an increase – not a decrease – in overall carbon emissions.
Its image as an energy saviour is also likely to sap investment in renewable energy sources, the report added. The Tyndall Centre concluded that the UK and Europe should halt shale gas development until more evidence is gathered in America about the potential harm fracking can cause.  

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