New research suggests shale gas is cleaner than coal


Independent research suggests that leaks of fugitive methane from fracking would have to exceed an implausibly high 12% before shale gas could be considered worse than coal in electricity generation.


In a paper published by the Centre for Policy Studies, Professor Robert Muller of the University of Berkeley California and Elizabeth Muller, co-founder and Executive Director of Berkeley Earth, a non-profit research organisation, say that because methane, the primary component of natural gas, is broken down in the atmosphere much more quickly than carbon dioxide released into the environment by burning coal, it would be necessary for implausibly large quantities of it to escape uncaptured for shale gas to be considered worse than coal.

Lee Petts, chief executive at the Onshore Energy Services Group, and himself an environmental consultant, welcomes this latest study: “Methane is acknowledged to be a more potent greenhouse gas than carbon dioxide, and it has previously been suggested that any fugitive emissions (leaks) during extraction could undermine the climate change benefits of using shale gas as a substitute for coal in power generation.

“But according to this latest research, earlier attempts at understanding the climate impacts of fugitive emissions have not properly taken into account a variety of factors, including the way in which methane is broken down in the Earth’s atmosphere, which mean it actually has a much lower global warming potential.

“The report authors have calculated that fugitive emissions of methane in fracking would have to reach over 12% in order to make shale gas worse than coal over a 20 year time horizon. To put that into context, 12% of the gas it’s thought it could be possible to extract from the whole of the Bowland shale under Lancashire and Yorkshire would be worth over £60 billion at today’s wholesale gas prices. Given that the aim is to maximise the amount of gas that can be supplied into the national grid and sold to consumers, nobody is going to waste any of this very valuable commodity if it can be avoided.”

Common practices in the USA, such as storing wastewater in open pits and routinely venting methane to air, have been associated with fugitive emissions at fracking sites there. But those practices are not permitted in the UK.

Regulations here mean that every effort must be made to capture and contain any gas that is encountered during the extraction process, for both safety and environmental reasons. The Offshore Installations, and Wells (Design and Construction) Regulations 1996 specifiy that operators must ensure wells are designed, built and operated to ensure that risks to the health and safety of persons from anything their wells might contain, including natural gas, are as low as is reasonably practicable. Similarly, permits granted under the Environmental Permitting (England and Wales) Regulations 2010 require operators to prevent unauthorised environmental discharges.

It means that flowback wastewater will have to be stored in tanks, not pits that are open to the atmosphere, and any unwanted gas will have to be burned in a flare rather than being vented.

“As well as any loss of potential revenue that is associated with fugitive emissions of methane during shale gas extraction, there are clear regulatory requirements to avoid any unplanned releases too. Operators risk having their sites shut down if they fail to comply with rules intended to protect workers and the public from harm. This powerful combination of financial and legislative drivers will motivate companies like Cuadrilla to keep fugitive emissions under control,” concludes Petts.

Other findings include:

When comparing coal to methane for equal electric power, the 20-year global warming potential (GWP) of methane compared to carbon dioxide is 11, not 86. The GWP of 86 assumes equal weights of methane and CO2, but methane is lighter.

Legacy warming from fugitive methane is minuscule compared to that of carbon dioxide. Only 0.03% of fugitive methane released today will still be in the atmosphere 100 years from now. In contrast, 36% of the carbon dioxide will linger.

Average leakage today is far below dangerous levels. The best estimates for the average leakage today, including by the US Environmental Protection Agency, are under 3%. Yet even with 3% leakage, natural gas would cause less than half the warming of coal.