Widely touted as a “missing link” to help decarbonise difficult sectors like steel, shipping, and chemicals production, the International Energy Agency anticipates global hydrogen demand increasing six-fold in a net-zero scenario.
The world’s major economies now all have massive programmes in place with the aim of leading the low-carbon hydrogen charge. The EU’s REPowerEU programme is aiming for ten million tonnes of domestic renewable hydrogen production by 2030, while the US is targeting an industry worth $140bn in revenues and 700,000 jobs by 2030.
But while lobbyists argue that hydrogen can be the “clean” fuel of the future, a growing body of studies suggests that there are climate concerns around even green hydrogen - produced from renewables, with no direct link to fossil fuel production - should it leak into the atmosphere during production, transport, or at storage sites.
A study produced by climate scientists at the Oslo-based CICERO Centre for Climate Research has found that leaked hydrogen has a global warming effect around 12 times greater than emitted CO₂. This is because hydrogen has a significant amplifying effect on the warming impact of certain greenhouse gases like methane and ozone, even though it is not itself a greenhouse gas.
“We used five different atmospheric chemistry models and investigated changes in atmospheric methane, ozone and stratospheric water vapour,” says CICERO senior scientist Maria Sand, who led the study. “A global warming potential of 11.6 is significant, and our study clearly shows the importance of reducing hydrogen leaks.”
“Reducing hydrogen leaks” makes sense in theory, as it will save producers money. But in practice, it is complicated by the fact that hydrogen molecules are much smaller and lighter than those of natural gas, and as a result are harder to contain.
There are also no readily available tools for measuring just how significant hydrogen leaks are; even more established methane monitoring systems vastly underestimate the scale of leakages. But a report from UK think tank Green Alliance offers some estimates: hydrogen heating pilots have found that leakage is around 1.2-3 times greater than is the case with natural gas while researchers at Columbia University in New York have forecast standard leakage rates of 3%-6%.
Modelling from Green Alliance has found that even a leakage rate of a few percentage points could massively reduce the climate benefits of hydrogen.
According to experts spoken to by Energy Monitor, such models should not simply prompt academic interest: They show that we should be genuinely concerned about the impact of hydrogen leaks as the industry undergoes a massive expansion in the coming years.
“It is definitely deeply concerning: Hydrogen is extending the lifetime of methane in the atmosphere, and methane is a hugely damaging greenhouse gas that is 80 times more potent at warming than carbon dioxide,” says David Schlissel from the Institute for Energy Economics and Financial Analysis (IEEFA). “This is a critical issue: we cannot go down a path now of spending hundreds of billions on a new energy system that may well accelerate climate change.”
Colm Britchfield, from the climate think tank E3G, adds that research such as this shows that leaked hydrogen could have a “hugely damaging effect”, and as a result, should not be deemed a “cure-all” for all our energy transition needs, particularly where it would need to be transported by pipelines over long distances.
“Some of the companies pushing hydrogen – particularly for heating - have no essential interest in being right about hydrogen, or about the hydrogen bet paying off”, he says. “Their main interest is simply to try and keep fossil fuel investment, and gas grid investment, where it is.”
