The International Organization for Standardization (ISO) this morning launched a new methodology for assessing the greenhouse gas emissions of hydrogen production at a COP28 high-level roundtable in Dubai.

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But it has already been criticised as simply calculating an emissions footprint at best, and greenwashing dirty hydrogen at worst.

A declaration to work toward mutual recognition of certification schemes signed by 37 countries — including the US, Germany, Japan and COP28 host the UAE — signposted the new ISO methodology as a globally recognised standard that national schemes could adopt or maintain consistency with.

“I would like to congratulate the COP28 Presidency on the work carried to advance low carbon hydrogen as the fuel of the future,” said Gerd Müller, director-general of the United Nations Industrial Development Organization (UNIDO), adding that the declaration and ISO methodology “will certainly contribute to that end”.

But critics have pointed out that the ISO methodology never sets a threshold of greenhouse gas emissions that would qualify hydrogen as “clean” — nor does it take into account that H2 is an indirect greenhouse gas in its own right.

Mark Brownstein, senior vice-president for the energy transition at US-based non-profit the Environmental Defense Fund, said: “The much-anticipated international standard for the deployment of hydrogen technologies was released at COP28. Unfortunately, the standard missed the mark in terms of ensuring the climate benefits we need from hydrogen. We’re going to have to do far better if we want hydrogen to play a constructive role in decarbonizing energy systems.”

Malcolm Turnbull, former Australian prime minister and chair of the Green Hydrogen Organisation — which yesterday set out its own updated Green Hydrogen Standard at COP28 — added: “Efforts to find a common method to calculate emissions from the production, conditioning and transport of hydrogen are welcome.”

“However, unlike the Green Hydrogen Standard, the ISO process underway will not include an emissions threshold for truly clean hydrogen.”

His views were echoed by Marta Lovisolo, senior policy advisor for renewable energy systems at non-governmental organisation Bellona.

“The ISO hydrogen standard announced today potentially increases confusion of what should classify as ‘clean’ hydrogen, instead of simplifying it,” she said.

“By failing to establish a threshold for emissions from hydrogen production, it is at best an emissions calculator — at worst a greenwashing tool for dirty hydrogen.”

Lovisolo noted that the methodology does not solve the issue of individual countries setting different emissions thresholds for clean hydrogen, “paving the way for a complex and fragmented future hydrogen trade”.

The ISO methodology has also been criticised for bundling together blue hydrogen, produced from fossil gas with carbon capture and storage (a process with a long history of underperformance), with H2 produced from renewables-powered electrolysis.

“It also risks underreporting emissions associated with blue hydrogen for upstream methane and the permanence of carbon storage,” said Turnbull. “As the ISO standard is developed, we need an inclusive and robust process to ensure these issues are addressed which take on board all views.”

Yuanrong Zhou, a researcher for the fuels programme at the International Council on Clean Transportation, added: “Under the methodology launched today, ISO-compliant hydrogen could potentially produce more greenhouse gas emissions than natural gas.

“ICCT’s research has shown that blue hydrogen, made from natural gas combined with CCS, poses serious climate risks from methane leaks and challenges in capturing carbon and storing emissions.”

Updated with new link to COP28 declaration of mutual recognition of certification schemes for renewable and low-carbon hydrogen and its derivatives, which lists 37 participants.