hydraulic fracturing sites in southwestern Pennsylvania has found that methane was being released into the atmosphere at 100 to 1,000 times the rate that the Environmental Protection Agency estimated.
The study, published Monday in the Proceedings of the National Academy of Sciences, found that drilling operations at seven well pads emitted 34 grams of methane per second, on average, much higher than the EPA-estimated 0.04 grams to 0.30 grams of methane per second.
The researchers, who were attempting to understand whether airborne measurements of methane aligned with estimates taken at ground level — the method commonly used by the EPA and state regulators — flew a plane over the region of the Marcellus Shale for two days in June 2012.
“The researchers determined that the wells leaking the most methane were in the drilling phase, a period that has not been known for high emissions,” reported the Los Angeles Times. “Experts had thought that methane was more likely to be released during subsequent phases of production, including hydraulic fracturing, well completion or transport through pipelines.”
Methane (CH4), the chief component of natural gas, makes up about nine percent of the country’s greenhouse gas emissions. It is a super-potent greenhouse gas — especially during the first 20 years after it enters the atmosphere when it traps around 86 times as much heat as CO2. So even small leaks in the natural gas production and delivery system can have a large climate impact — enough to gut the entire benefit of switching from coal-fired power to gas.
Paul Shepson, an atmospheric chemist at Purdue University who worked on the study, told the Los Angeles Times that while more research is needed to determine whether the extremely high measurements are typical, the vast disparity between the readings illustrates the limitations of the current methods. “The EPA’s approach puts regulators at the mercy of energy companies, which control access to the wells, pipelines, processing plants and compressor stations where methane measurements should be made, ” he continued.
This study adds to the growing literature on the critical role methane emissions play in contributing to climate change, and the need for better data and improved means of reducing emissions. A recent comprehensive Stanford study reviewed over 200 earlier studies to find that “U.S. emissions of methane are considerably higher than official estimates,” and that “leaks from the nation’s natural gas system are an important part of the problem.”
Less than two weeks ago as part of President Obama’s Climate Action Plan — which involves addressing climate change without the help of legislation from Congress — the White House released a preliminary strategy to reduce methane emissions from a variety of sources including landfills, agriculture, and the fossil fuel industry. The plan calls for the EPA to study what sort of regulations may be needed to comply with the Clean Air Act. If the agency decides to issue new rules they must be in place by the end of 2016 when Obama leaves office.