Impacts of fracking on water supply
Fracking - short for "hydraulic fracturing" - involves drilling deep under ground and releasing a high-pressure mix of water, sand and chemicals to crack rocks and release gas stored inside. Fracking has raised some interesting questions in my energy talks. Is it good or bad? Should it be allowed in the UK? One of the expressed concerns is the impact on our water supply.
Firstly, when comparing the US/UK situation, it's worth remembering that the US is 40 times bigger in area, but its population is only 5 times bigger. It therefore has a much lower population density and a lot of space where fracking can occur without impinging on local communities. Exploratory oil and gas drilling by energy company Cuadrilla Resources in Balcombe, West Sussex in 2013 has been front page news partly because it is happening in a densely populated area that is very much in the spotlight. In response to this, Lord Howell of Guildford, a former energy secretary, infamously got himself into hot water by unconsciously wishing for the US geographical scenario by suggesting fracking should be carried out in the North East of England, where there are large, "desolate" areas.
Water companies may worry that it will contaminate aquifers that we draw our drinking water from. In 2012 the UK Government’s Chief Scientific Adviser, Sir John Beddington FRS, asked the Royal Society and the Royal Academy of Engineering to review the scientific and engineering evidence and consider whether the risks associated with fracking as a means to extract shale gas could be managed effectively in the UK. Their report ('Shale gas extraction in the UK: a review of hydraulic fracturing') makes many recommendations as to how wastewater (containing 5% sand and 0.17% chemical additives) could be safely managed and points out the relatively small amounts required. The chemical additives are things like biocide to make sure bugs don't clog up the pipes and hydrochloric acid to dissolve excess cement in the pipe bore. Of this 0.17% of chemical cocktail, only about 20% does not remain in the ground and has to be dealt with as wastewater. They find no conclusive evidence of aquifer pollution in the US, whilst agreeing that the British Geological Survey should be encouraged to build up baseline data on normal methane levels in groundwater to then make it possible to more accurately assess if subsequent fracking degrades water quality through the introduction of leaked methane, which has been seen in the US within a kilometre or two of some wells. Generally, fracking occurs in rocks several thousand metres below groundwater reservoirs, and so the British Geological Survey regard contamination as unlikely.
There are big differences though between the experience of the US and what is likely to happen in Britain. The US has a different geology, different drilling methods and different regulations. In the UK, the drilling companies are engaging with water utility companies. There is uncertainty as to whether there is any risk and the emphasis is being placed on exploratory studies. Each hydraulically fractured shale well needs around 19,000 cubic metres (4 million gallons) of water to operate over a decade. this sounds a lot, particularly in the water scarce South East of England, but let's put that in perspective. 19,000 cubic metres is a cube of water around 26m on all sides. Or the amount needed to water a golf course for a month. Or the amount needed to run a 1,000 MW coal-fired power plant for 12 hours. Or the amount lost to leaks in United Utilities’ region in northwest England every hour. Or the amount used in a typical canal lock. "While shale production is undeniably a water intensive business, it still requires much less water than many other, more familiar, water consumers" (Moore, 2012, 'Gas Works? Shale gas and its policy implications'). But of course, if there are several thousand wells in the south of England alone, as has been mooted, then the drain on the water supply may become critical.
There are many pros and cons regarding fracking that will be considered in other posts. But at the moment, I don't see an overwhelming argument against fracking based on water issues alone.
This is just one of the stories from my energy talk