AGA slams Cornell shale-gas study
Emissions claim 'inaccurate and misleading'; greater scrutiny of the report's data required
THE American Gas Association (AGA) has slammed a Cornell University report that claims life-cycle greenhouse-gas (GHG) emissions from shale-gas could be higher than those for coal, branding the study "inaccurate" and "misleading".
The report – "Methane and the Greenhouse-Gas Footprint of Natural Gas from Shale Formations" – claims methane emissions from shale-gas production are "at least 30%" and "perhaps more than twice as great" as those from conventional gas. Methane is about 20% more damaging as a GHG than carbon dioxide (CO2).
The report, to be published in the scientific journal Climatic Change this week, follows a preliminary study released last year. In that report, lead author Robert Howarth, a professor of ecology and environmental biology at Cornell University, claimed shale-gas development emits more GHGs than coal production.
The latest study, also led by Howarth, claims the higher emissions from shale gas can occur at the time wells are hydraulically fractured – as methane escapes from flow-back return fluids – and during drill out following the fracturing.
The Cornell study goes on to state that between 3.6% and 7.9% of the methane from shale-gas production escapes into the atmosphere through venting and leaks over the lifetime of a well. And controversially claims that over a period of 20 years, shale gas's carbon footprint is "at least 20% greater" than that of coal.
'Inaccuracies and hyperbole'
But Dave McCurdy, chief executive of US gas-industry group AGA, condemned the study, claiming it is full of "inaccuracies and hyperbole". He added: "By any measure, natural gas is the cleanest fossil fuel. We cannot afford to let our thoughtful policy decisions be side-tracked by studies that bear no resemblance to reality."
Wolf Regener, chief executive of BNK Petroleum, which has shale-gas acreage in Poland, Germany and Spain, told PEU it "just doesn't make sense" for shale gas to have higher emissions than conventional gas or coal.
And Dennis Carlton, executive director of Cuadrilla Resources, which is exploring for shale gas in northern England, told PEU he also disagrees with the findings. "There's physically no reason for shale gas to release more methane [than conventional gas production]," he said. "If we have a leak, it's a wellborn integrity problem and could be common to conventional gas as well."
Carlton added that for an industry focused on delivering large volumes of gas to market as quickly and cheaply as possible, carelessly allowing leaks doesn't make good business sense.
Carlton said Cuadrilla may push for greater scrutiny of the report's data. But if the claims prove to be true, Cuadrilla will take steps to limit its environmental footprint, he said. "If there's hard evidence then we'd like to see it and compensate," he told PEU, "We're open to positive change."
But the perception of an environmentally corrupt natural gas industry is partly a result of the sector's failure to engage with the public, Carlton said. "The energy industry, especially in the US, hasn't been very good at educating the public," he said. "But does the public want to be educated by an energy company? Probably not. They just want cheap energy."
In January, the UK's University of Manchester released a report claiming there was a risk of ground-water contamination from shale-gas production. The study called for a moratorium on drilling until there is a more thorough understanding of the extraction process and its environmental impact.
Paul Gilbert, a co-author of the report, told PEU he was "surprised" at the Cornell report's conclusions because the availability of data is "scarce" regarding emissions from shale gas.
Advocates for natural gas claim it could be an important "transition fuel" on the path to a lower-carbon energy industry. But Gilbert said unconventional gas will "miss the boat" as a transition fuel because it will be unlikely to make a significant contribution to energy supplies outside North America before 2025. This will be "too late", he said, to restrain global warming to within the 2Â°C level that scientists say will be essential to limiting climate change.
Pro-shale-gas campaigners frequently cite the environmental benefits of natural gas, which emits around 50% less CO2 than coal when burnt for power generation, as a factor in its favour.