Scientists reiterate concerns about climate-warming hydrogen leaks

As the science about the climate impact of hydrogen becomes clearer, discussions on whether a dedicated law is needed to detect and repair leaks from infrastructure are also gaining momentum.

With the COP28 climate summit opening in Dubai on 30 November, scientists are drawing attention to lesser-known gases whose climate warming effects have so far been overlooked. 

Hydrogen, a clean-burning gas, is widely expected to replace fossil fuels in industries like chemicals and steelmaking, but experts have also warned about the potential leakage of the gas and its related climate impact.

While hydrogen in itself does not cause climate heating, it reacts with other gases in the atmosphere to make their warming effect even more powerful.

“Hydrogen is a strong indirect greenhouse gas,” explains Steven Hamburg, chief scientist at the Environmental Defend Fund, a global non-profit group dedicated to tackling climate change. 

According to EDF’s current estimates, the climate impact of hydrogen is about 34 times higher than CO2 when measured over a 20-year period. Looking at the impact over 100 years, the global warming potential reduces to between eight and 13 times.

Hydrogen causes this by stabilising methane in the atmosphere and creating tropospheric ozone and stratospheric water vapour, Hamburg told participants at a recent Euractiv event supported by EDF. 

While debates on hydrogen policy have so far centred on green production standards, Hamburg says tackling leakage was also crucial to “ensure that we get the [climate] benefits that we want”.

Today, nobody is keeping track of how much hydrogen leaks in the atmosphere from human activity, even though the molecule is highly volatile and flammable.

While the hydrogen economy is currently tiny, it is projected to ramp up fast to replace fossil fuels in areas like steelmaking, cement production, maritime shipping and potentially aviation. 

By 2030, the EU plans to produce 10 million tonnes of renewable hydrogen made from green electricity and import 10 million tonnes of it.

And as production increases, the risk of hydrogen leaks increases as well. According to the Center on Global Energy Policy at Columbia University, the leakage rate could reach 5.6% across the economy, compared with an estimated 2.7% in 2020.

That doesn’t mean that an immediate clampdown on hydrogen is needed, says Hamburg.

“We need to have a scientific consensus on the warming effects, which we are now building and is increasingly robust, and we need to know how much hydrogen is lost to the atmosphere,” he stressed.

Scientists warn against global warming effect of hydrogen leaks

Recent studies suggest that hydrogen could be a contributor to the greenhouse effect when it leaks through infrastructure.

A new law to tackle hydrogen leakage?

EDF has warned policymakers about the risks of hydrogen leakage for years now.

Slowly, their efforts are starting to bear fruit, with the International Energy Agency (IEA) now acknowledging the issue.

“This problem has been quite overlooked in the last few years,” admitted Jose Bermudez, an energy technology analyst at the IEA who spoke at the Euractiv event. 

Since then, research has been released offering new insights into how the gas can leak into the atmosphere.

“We need to make a really strong effort on collecting information, gathering data and better understanding the problem in all sorts of equipment that uses hydrogen,” Bermudez said. 

And as more hydrogen projects keep sprouting from the ground, “we need to make sure that companies entering the hydrogen sector as part of this new wave, prioritise measurements,” the IEA’s Bermudez added.

Yet, creating a law on hydrogen leakage may be premature, says Jan Rosenow, Europe director at the Regulatory Assistance Project (RAP), a think-tank.

Instead, channelling climate-friendly hydrogen into “no-regret” options like fertiliser production should come first, he argues, saying the lack of demand for clean hydrogen needs to be tackled before leakage.

Europe has “not spent enough time yet on thinking about how we actually create the right conditions to stimulate hydrogen demand,” Rosenow explains, especially “in those sectors where we know it’s going to be desperately needed”.

The IEA’s Bermudez agreed, adding that “policy work on hydrogen leakage” would be contingent upon building an “evidence base.”

And in all, the IEA analyst said he wasn’t too concerned going forward.

“There is a strong incentive for companies that are going to make business out of hydrogen to take seriously the issue of leakage,” he explained, adding that he expects “the potential impact of hydrogen on global warming to be limited.”

For EDF though, the experience with methane, a gas which until recently was widely overlooked, offers a cautionary tale. Even before the European energy crisis, around half of global methane gas leaks could have been avoided at no cost because selling the gas would have recovered the cost of intervention. 

“Until we measured, people didn’t realise how their systems actually operated. They were losing product and would tell you they’re not,” recounts Hamburg.

“We’re pretty confident that’s happening.”

> Watch the full video recording of the Euractiv event below:

This article follows the Euractiv-organised policy debate “Hydrogen emissions – What implications for the green transition?” supported by the Environmental Defense Fund.

[Edited by Alice Taylor and Frédéric Simon]

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