Much has been said about the controversial process of fracking for natural gas in recent months, particularly in light of the protests in the Sussex village of Balcolme. But what exactly is it and why is it so contentious? In the fracking process a vertical well is drilled to a set depth, from which drilling proceeds horizontally through gas-bearing shale formation. A high pressure mixture of water, chemicals and sand is then pumped into the well, which causes the subsurface rock to fracture and the gas to be released. Whilst fracking has been known about since the 1950s, it was formerly too expensive to extract gas by this method. Prices have now reached the tipping point where this is changing. Supporters of fracking say that this new supply of gas will improve domestic energy security and help keep costs down. The UK has large reserves of shale gas and will need to rely less on imports from volatile markets and it will provide jobs. There are advantages to burning gas over still-plentiful coal, namely lower CO2 emissions and much lower levels of pollutants.
However, the environmental risks of fracking are considerable and poorly understood over long time scales. The vast amounts of fresh water that are required place a huge strain on already stretched supplies. Gas that is released in the shale formations can make its way into the water supply in concentrations high enough to cause tap water to become flammable. Whilst not previously thought to pose a health risk, the effects of such high levels of dissolved methane in drinking water have not been fully investigated. A far more sinister danger is that waste water created during the fracking process can leech into the water table. This waste water contains chemicals used in the fracking process – a toxic blend of no fewer than 700, several of which are known or suspected carcinogens – and radioactive elements such as radium which are present naturally in the subsurface rocks. This cocktail is so potent that it cannot be treated and recycled like normal sewage. Fracking has also been known to trigger earthquakes, although according to a Royal Society report, the effects are minor and have been overstated.
A continued reliance on natural gas locks us in to carbon intensive electricity generation for the foreseeable future, doing nothing to incentivise the energy industry to provide climate friendly alternatives. The environmental cost of fracking is higher than for conventional gas as it requires more energy and raw materials to extract from shale, further exacerbating the problem. Another significant issue is the small fraction of gas that inevitably escapes from fracking wells, as methane is a much more potent global warming agent than carbon dioxide.
Not with standing the problems, could a supply of domestic gas bring down energy prices here in the UK? David Cameron and George Osborne seem to think so, citing the US shale gas boom as an example. Others in government disagree, for example Energy and Climate Change secretary Ed Davey and respected economist Lord Stern, with the latter saying the Premier’s claims were grounded on “baseless economics”. Whatever the arguments for and against, it seems plausible, even likely, that fracking will become part of the UK energy mix in the future. At the very least, further research is needed to overcome some of the very real dangers associated with this controversial technique.
Check out this short video from Zurzgesagt for an additional explanation