Is natural gas sustainable? Temporarily yes, the EU Commission thinks: According to a draft law published this week, new gas-fired power plants should be considered climate-friendly at least until 2035 if they meet certain requirements – for example if they replace even dirtier coal-fired power plants. An actual Study in Science Journal Science raises new questions about the energy source natural gas. In particular, the extraction and transport of fossil fuels cause more climate-damaging greenhouse gas emissions in many places than previously known.
The climate researchers around Thomas Lauvaux from the University of Saclay near Paris concentrated in the study on so-called “ultra emitters” of methane: sources from which a particularly large amount of the gas flows into the air. Methane (CH₄) is a main component of natural gas and at the same time a greenhouse gas that, calculated over 20 years, heats the atmosphere 80 times more than the same amount of carbon dioxide (CO₂). Although methane only stays in the atmosphere for a comparatively short time, global emissions have continued to rise in recent years. Every year, another 50 million tons of methane are released into the atmosphere, which contributes significantly to global warming. Along with agriculture and landfills, the oil and gas industry is a major source of emissions. The methane often escapes unnoticed and therefore does not appear in greenhouse gas balances.
The scientists working with Lauvaux searched the recordings of the European earth observation satellite Sentinel-5P, launched in 2018, for evidence of such sources. During the observation period from 2019 to 2020, they discovered around 1,800 very large methane leaks worldwide, each of which emitted more than 25 tons of gas per hour. Two-thirds of these wells are located near oil and gas processing infrastructure. A large part of the “anomalies” are concentrated in a few countries: Russia, Turkmenistan, the USA, Iran, Kazakhstan and Algeria.
It would even be profitable to plug the leaks – but oil companies often do without it
In particular, the values about Turkmenistan stand out. The researchers estimate that “ultra emitters” are responsible for 1.3 million tons of methane per year in the authoritarian state on the Caspian Sea. This means that the actual emissions from the Turkmen oil and gas industry would be twice as high as officially stated. “These enormous leaks in Turkmenistan surprised the scientific community. It seems to be happening more or less on purpose,” says Lena Höglund-Isaksson, who researches greenhouse gases at the International Institute for Applied Systems Analysis (IIASA) in Laxenburg, Austria.
But why would anyone let gas escape into the atmosphere when you could sell it too? But why throw gas away? This often happens even when companies are actually looking for oil. A lot of “associated gas” also flows to the surface in oil fields. To prevent it from entering the atmosphere directly, drill crews would have to either flare it off – a practice known as “flaring” – or contain it, which requires tanks or pipelines. The study in Science shows that such investments almost always pay off, because the gas collected can be sold for significantly more than the investment costs. However, the profit margins are usually lower than if you ignore the leaks and expand production. “It’s just more profitable to drill more holes and pump up more oil,” says Höglund-Isaksson.
Turkmenistan appears to be at the forefront of this practice, followed by Russia, where major gas leaks release around a million tons of methane a year. This can also happen during maintenance work on tanks or pipes if little attention is paid to escaping gas. The largest leaks can release hundreds of tons of gas per hour and create gas plumes hundreds of kilometers long. The USA is a long way behind in third place, although the researchers excluded the largest American production area, the Permian Basin, from the analysis. The winding towers are so close together there that it was not possible to delimit individual leaks. In an accompanying comment in Science However, the climate researcher Felix Vogel from the Canadian Ministry of the Environment points out that “thousands of oil and gas wells in Canada and the natural gas transport infrastructure in US cities” are also among the super emitters.
A global inventory of methane sources could be crucial to holding the biggest emitters to account, Vogel said. Lena Höglund-Isaksson says that until recently it was almost impossible to detect such leaks. “Being able to finally see methane dumping is a major breakthrough.” In the next few years it is expected that new satellites will provide an even more precise picture – then it should even be possible to assign emissions to individual companies.
According to a report by the UN Environment Program, in addition to CO₂ emissions, which contribute most to the greenhouse effect, methane emissions must also fall quickly so that the goals of the Paris climate agreement can still be achieved. “Forcing the oil and gas industry to do this,” says Höglund-Isaksson, “is the cheapest, easiest way to do it.”