The following is an extract from a research piece entitled 'The future of UK shale gas" and is the final article in a series on environmental concerns related to fracking.
Proponents of shale gas exploration often cite the perceived benefits to climate change that arise due to fracking. When compared with coal-fired production, natural gas emitted half as much carbon dioxide, less than a third as much as nitrogen oxides and a hundredth of sulphur dioxide. The US Energy Information Administration (EIA) indicates that anthracite coal produces 228.6 pounds of CO2 per million British Thermal Unit (BTU) of energy, whereas natural gas emitted 117 pounds, a reduction of 49%.
Even when the additional greenhouse gases derived from the extraction, treatment, and transporting of natural gas to power plants are taken into consideration, carbon emissions remain lower than other fossil fuels. A report on behalf of the UK's Department for Energy and Climate Change (DECC) summarised that the carbon footprint of shale extraction was likely to be between 200 - 253g of CO2 per kWh of chemical energy, compared with the carbon footprint of conventional sources (199 - 207 g CO2/kWh) and Liquefied Natural Gas (233 - 270g CO2/kWh). MacKay and Stone also found that when shale gas was utilised for electricity generation, its carbon footprint was in the range of 423- 535 g CO2/kWh, significantly lower than coal's carbon footprint, which is 837 - 1130 g CO2/kWh.
The carbon footprint changes when methane (which has a 'global warming potential' 25 times that of carbon dioxide over 100 years) from leaking wells is taken into consideration. A report by the EPA lowered estimates of methane leakage from 2.8% to 1.65% in 2011. The view that methane leakages were minimal is supported by evidence from the University of Texas, which indicates emissions from fracking flow back operations alone ranged from 0.01 mega grams to 17 mega grams - substantially lower than the average 81 mega grams which was estimated by the EPA. However, the study "Methane Leakage from North American Natural Gas Systems," published by the journal Science, synthesizes 200 studies and contradicts the findings of the EPA. Adam Brant, the lead author of the analysis and assistant professor of energy resources engineering at Stanford University, said that methane emissions were "around 50% more than EPA estimates... and that's a moderate estimate." Despite this, Brant and his team hold the view that natural gas has a smaller climate impact when compared with coal over a 100-year period. The Intergovernmental Panel on Climate Change (IPCC) also holds the view that natural gas can act as a "bridge" between carbon-intensive coal and renewables. However, it stipulated in its Working Group III report that natural gas would only be effective as a bridge form of energy if gases released into the atmosphere during extraction and distribution (namely methane) could be controlled. Finally, the Committee on Climate Change indicates shale gas is environmentally superior to shale gas providing the methane leakage rate is below 11%, which most academic studies suggest it will be below.
The effect natural gas has on climate change will be positive if methane emissions can be controlled. If the methane leakage rate can be limited to 2%, as supported by the EPA in 2011 (with a rate of 1.65%) and a coal-to-gas conversion rate of 5% is maintained, shale gas can contribute towards a 50% reduction in emissions within 60 years. Whilst it may take up to 60 years for shale gas to achieve its full potential environmental benefit, fracking has had an immediate environmental benefit and research indicates it will complement renewable energy. Since the availability of cheap gas in the US energy markets, coal electricity fell from 48% of the energy market to 37%. Furthermore, America's shale revolution has aided the reduction of its carbon emissions to 1995 levels. With no dependant renewables available immediately, the UK requires a bridge fuel or risks being dependant on dirtier coal until technological advances render renewables steadfast.
Fracking is the sensible middle ground between preserving the environment and satisfying our energy needs. The industry is undeserving of the hysteria disseminated by opponents who threaten to jeopardise an energy source which is potentially beneficial to communities, the environment and consumers. The environmental concerns are wildly overstated and the energy industry should be more concerned with well depletion rates and the higher cost of extraction in the UK.