The dark side of natural gas

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The world’s appetite for natural gas is booming. In the U.S., natural gas production is at an all-time high and poised to go up even more. That’s widely considered to be good news for the climate since burning natural gas produces about half as much carbon dioxide as coal.

But a new study shows that natural gas is far from a clean alternative to dirty coal. The potent greenhouse gas methane, the main ingredient in natural gas, has been leaking from the U.S. oil and gas production chain at 60 percent higher rates than previous government estimates, according to the report published in Science.

The new analysis shows that around 2.3 percent of methane escapes into the air at U.S. oil and gas wells, pipelines, and processing plants, amounting to around 13 million metric tons a year. The Environmental Protection Agency had pegged leaks at 1.4 percent.

These seemingly small numbers have a huge impact. Methane is 80 times more potent than carbon dioxide as a greenhouse gas over a 20-year period, and experts believe it is responsible for a quarter of the planet’s warming so far. So over 20 years, the leaked methane in the U.S. would have as much planet-warming impact as the annual carbon dioxide emissions from all US coal-fired power plants operating in 2015, the study’s authors write.

To calculate the new number, a research team led by scientists at the Environmental Defense Fund (EDF) gathered data on the ground and from the air. They measured methane levels in the air around natural gas wells, storage tanks, refineries, and underground distribution pipes. They also took conducted aerial surveys, using infrared cameras to spot and measure leaks. The measurements were done in key gas-producing areas that made up around a third of American gas production.

Methane leaks are hard to measure accurately. The new results imply that the EPA’s methods for emissions measurements might be inaccurate or outdated. The EDF team’s aerial surveys, for instance, found that an abnormally high percentage of leaks were due to equipment failure and operator errors, mostly from the vents and hatches of storage tanks.

In addition to harming the climate, methane leaks are a huge waste of a valuable resource. The amount of gas lost could power 10 million homes a year and had a value of $2 billion, the study team concludes.

The good news is that new technologies could provide a cost-effective fix for the problem. The International Energy Agency estimates that the oil and gas industry can reduce its methane emissions by 75 percent. Up to two-thirds of those reductions can be realized at zero net cost.

The EDF is calling for a 45 percent reduction in methane emissions by 2025. Achieving this goal would have the same short-term climate benefit as closing one-third of the world’s coal plants. “Federal and state governments must take action – and many states are – but industry leadership remains crucial,” said EDF Senior Vice President Mark Brownstein.

Source: Ramon A. Alvarez et al. Assessment of methane emissions from the U.S. oil and gas supply chain. Science, 2018.

Image: giphy

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