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US oil and gas industry methane emissions up to 60 per cent higher than EPA estimates

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A study involving scientists from 15 institutions and published in Science has found that methane emissions by American gas and oil bodies may have been vastly underestimated by the Environmental Protection Agency (EPA).

Methane – the primary ingredient in natural gas – is a greenhouse gas. Once released into the atmosphere, it absorbs heat far more effectively than carbon dioxide, with a global warming potential more than 100 times that of carbon dioxide over 20 years. This renders the gas an important target for climate mitigation efforts.

Much of the world’s methane comes from agriculture, landfills and waste treatment, although the largest industrial source of methane is gas leaks. The environmental impact of methane leaks in 2015 was estimated to be as harmful as that of all carbon dioxide emissions from coal power plants in the US. In 2016, the EPA introduced rules to limit these emissions by oil and gas companies.

More recently, however, the Trump Administration has been making moves to roll back restrictions on methane operations.

The large collaboration of scientists assessed numerous measurements, including measurements of methane emissions across 400 oil and gas production basins. They were able to conclude that the US oil and gas industry emits 13 million tonnes of methane per year, 60 per cent more than the EPA had estimated. This gas is worth an estimated $2bn (£1.5bn) and could heat 10 million American homes.

“This study provides the best estimate to date on the climate impact of oil and gas activity in the US,” said Jeff Peischl, a National Oceanic and Atmospheric Administration (NOAA) scientist and co-author of the study. “It’s the culmination of 10 years of studies by scientists across the country.”

The researchers found that most of these emissions could be traced back to leaks and other “abnormal” operating issues. They suggested that the EPA may have underestimated the true extent of methane emissions, due to the agency seeking permission from oil and gas companies to take their measurements, resulting in measurements being taken when all equipment is working at a higher standard than usual.

“Natural gas emissions can, in fact, be significantly reduced if properly monitored,” said Colm Sweeney, a scientist at NOAA. “Identifying the biggest leakers could substantially reduce emissions that we have measured.”

Emissions as high as those found by the study, published in Science, would erode the potential environmental benefit of transitioning from coal to gas, as governments and companies attempt to reduce greenhouse gas emissions in accordance with the Paris Agreement, which aims to prevent average global temperatures rising more than 2°C above pre-industrial levels.

An EPA spokesperson told Reuters that the agency would be looking at the findings.

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