By Nikolaus J. Kurmayer | EURACTIV.com
Scientists have warned that hydrogen could be a significant “indirect” contributor to the greenhouse effect when it leaks through infrastructure and interacts with methane in the atmosphere.
Last year, the European Commission presented a hydrogen strategy, saying that clean hydrogen could meet 24% of the world’s energy demand by 2050 and help decarbonise hard-to-abate industrial sectors like steel and chemicals.
Hydrogen only releases water vapour when burned, prompting policymakers to put their hopes into the new gas as a way of tackling climate change.
But hydrogen itself is an indirect contributor to global warming, said Steven Hamburg, chief scientist at the Environmental Defense Fund (EDF), a US-based non-profit group.
And its effect on the climate has so far remained largely unexplored.
“Hydrogen is a potent short-lived indirect greenhouse gas that is 200 times more potent than carbon dioxide at the time it is released, kilogramme for kilogramme,” Hamburg told EURACTIV.
Hamburg is a former professor of environmental science who served as a lead author for the UN’s Intergovernmental Panel on Climate Change (IPCC). He says hydrogen is problematic because it interacts with methane in the atmosphere.
“Hydrogen that leaks to the atmosphere is such a potent greenhouse gas because it extends the lifetime of methane in the atmosphere, causing it to stick around and continue contributing to the greenhouse effect,” he told EURACTIV.
“Hydrogen reacts to form tropospheric ozone, which also contributes to the greenhouse effect. And hydrogen also breaks down into water vapour in the stratosphere, which also contributes to the greenhouse effect,” he added.
Hydrogen is such a potent indirect greenhouse gas that it “could undermine the climate benefits of decarbonisation efforts,” warned Ilisa Ocko, a senior climate scientist at the EDF, who spoke at a EURACTIV event on 29 September.
When these atmospheric effects are taken into account, the climate benefits of replacing fossil fuels with hydrogen becomes less clear, she cautioned – even when hydrogen is produced from renewable electricity. More details…