Cuadrilla temporarily halted fracking at its Preston New Road facility in Lancashire, the only active shale gas exploration site in the UK, on August 21, 2019. This followed a micro-seismic event (a mini-earthquake) measuring 1.55 on the Richter scale. Cuadrilla had started operations at the site in October 2018, marking the resumption of fracking in the UK after it had been halted in 2011. The incident provided further ammunition to anti-fracking campaigners in Britain, where fracking has never gained wide popularity.
Dwindling reserves of fossil fuels such as crude oil and natural gas have led to the development of alternative fossil fuel sources, paradoxically at a time when renewable energy sources are gaining in popularity. Fracking is particularly widespread in the US, where the consequent energy boom has helped lower energy costs and reduce a dependence on energy imports.
Fracking is the short form of hydraulic fracturing. Wells are initially drilled deep inside the earth. Vertical drilling to a depth of one to two miles or more is followed by horizontal drilling in several different directions. Once the drilled wells are cased and cemented, small perforations are made in the horizontal sections of piping
A mixture of water, sand and a variety of chemical additives is pumped into the well system at high pressures by the use of compressors. This creates micro-fractures in the shale-bearing subterranean rock formations, thereby releasing shale gas and oil. Sand keeps the micro-fractures open and the additives help reduce friction and prevent corrosion of the pipes. The released gas is processed for usage and the residual contaminated waste water is either injected into deep underground wells or removed for further treatment at off-site facilities.
Fracking is an American innovation, and the US continues to lead the world in shale gas and oil production. Hydraulic fracturing techniques began to be developed in the US during the 1940s, and commercial fracking operations were started in 1949 by Halliburton. The Great Plains, the Great Lakes and the Marcellus Shale are the main fracking areas in the US.
Any source of energy requires balancing of any environmental impacts against the potential economic benefits. In the US, fracking has led to a new oil and gas drilling rush and contributed to economic growth. Private-sector employment has increased through the creation of new drilling, extraction and support jobs. Government revenues from rents, taxes and royalties have also risen. A lowered reliance on energy imports had led to a more favourable energy trade balance, which is tipping in favour of increased exports.
There are, however, many potential sources of environmental damage. Land has to be cleared for well sites and the associated infrastructure, including oil tanks, pipelines and roads. This destroys natural habitats and has a negative impact on local animal and plant life. There is a risk of air, water and noise pollution. Air quality is compromised by emissions from diesel-powered pumping equipment, flared (burned) and vented (released into the atmosphere) gases, and engine exhausts from increased truck traffic. Groundwater and surface water pollution can result from the leakage of fracking fluids into underground aquifers. Water shortages can result from excessive use of water in the fracking process. And then there is the loud noise caused by drilling, which leads to sound pollution.
The greatest potential for shale gas and oil extraction in the UK is from the Weald Basin (between the North and South Downs) and the Bowland Shale (Lancashire and Yorkshire), where local campaigners have successfully opposed fracking operations. Specific concerns arise from potential damage to national parks and Areas of Outstanding Natural Beauty, as current policy allows for drilling for fracking at depths of 1200 metres or more in these areas. Putting things in perspective, it is worth reflecting on the relatively small size of England and the proximity of potential fracking sites to major centres of population. In contrast, one of the main shale gas producers in the US is the sparsely-populated state of North Dakota, which alone is almost one-and-a half times the size of England.
The jury is still out on fracking. It would appear that the US provides us with a natural laboratory to study the long-term impacts on the environment and on public health. Fracking has yet to take off worldwide, although Canada, China and Argentina are also involved with the commercial production of shale gas and oil. Any good case for justifying fracking in the UK has yet to be made, especially with the growing imperative to meet tight carbon emission targets
Ashis Banerjee