Wednesday 3 August 2022

‘Hydrogen leaks could mean it’s not so green after all’

Hydrogen molecules can leak, reducing the environmental benefits of the gas by up to 80%.

That’s according to non-profit Environmental Defense Fund (EDF), which claims that in the quest to hit net zero, the impact that hydrogen leaking can have on the environment is being increasingly overlooked.

On green hydrogen, EDF scientists stated: “Billions in new investments and financial subsidies are being proposed to speed adoption. Nevertheless, hydrogen itself has significant climate impacts that are both widely overlooked and underestimated and it is a very small molecule that can easily leak into the atmosphere from infrastructure.”

Hydrogen molecules are around eight times smaller than methane molecules, which makes leaking far more likely, the research stresses.

It reveals that in a ‘best-case scenario’, leakage of hydrogen could be 1% – but it could get as high as 10% in some cases.

A 1% leak would see around 0.025°C added to the Earth’s temperature by 2050 – however, 5% to 10% could lead to 0.1°C or 0.4°C increases, the scientists allege.

They state: “Our results indicate that hydrogen emissions can considerably undermine the climate benefits of decarbonisation strategies that involve clean hydrogen – especially in the decades immediately following deployment. Minimising leakage will be essential to the effectiveness of hydrogen as a climate change mitigation strategy.”

To combat leakage issues, the researchers claim that designing new pipelines specifically for hydrogen rather than retrofitting ones currently used for natural gas would help. However, the cost of this is not something many governments are pleased with.

It estimates that by 2050, one-eighth of the world’s hydrogen will most likely be transported using retrofitted pipes.

However, the report warns: “We have the rare opportunity to get ahead of this issue before the infrastructure and systems are widely deployed.”

The scientists recommend the development of more technologies to accurately measure the emissions of hydrogen when being used as an energy source – and using these findings to help build suitable infrastructure.

“If we are to meet the climate challenge before us, it is imperative that we carefully examine each alternative decarbonisation pathway using robust and appropriate metrics and data,” the study concludes.