The chair of the Scottish Government's just transition commission has ripped a hole in the SNP’s renewed independence case after insisting there is no evidence the country can export renewable hydrogen abroad.

The Scottish Government’s updated case for independence brands renewable hydrogen as potentially “Scotland’s greatest industrial opportunity since oil and gas” amid claims it could create up to 300,000 green jobs – almost double the number working in the NHS in Scotland.

Climate campaigners have criticised the “pie-in-the-sky predictions” by the Scottish Government over the potential expansion of hydrogen.

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The blueprint making the economic case for independence claims that Scotland “has significant hydrogen expert potential” for renewable hydrogen, with SNP Net Zero Secretary Mairi McAllan pointing to Germany and the rest of Europe when pressed over the issue by The Herald.

Hydrogen is seen by some climate activists as controversial, given some grades such as grey or blue hydrogen allow fossil fuels to continue to be burned – producing carbon which will need to be captured and stored through technology yet to be scaled up and used commercially.

Green hydrogen essentially splits water molecules into oxygen and hydrogen, with the electrolysis process powered by renewable electricity.

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Hydrogen can replace fuel in vehicles, while trials are underway for boilers to use the fuel instead of methane to heat homes.

The Scottish Government has claimed that an independent Scotland could produce more green hydrogen than meets demand and be able to commercially expert the renewable fuel overseas.

But in a scathing assessment of the Scottish Government’s plans, Professor Jim Skea, the chairman of the government’s own just transition commission, has warned there is no evidence to suggest that Scotland could export the fuel.

He said: “One of the main points we picked up with the draft energy plan was the quite aspirational nature of some of it.

“For example, in relation to hydrogen, the assumption was that a lot of the market might lie in export opportunities and we didn’t see the evidence there for that to justify where these markets were going to be.

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“Unless you have clear ideas about realistic plans in areas like that, I think it’s going to be very difficult to be precise about the opportunities are….”

Friends of the Earth Scotland climate campaigner, Alex Lee, said: “Everyone concerned about our energy future should be extremely sceptical about the Scottish Government's pie-in-the-sky predictions about hydrogen.

“It is not really credible for ministers to speculate that the hydrogen economy could employ twice as many people as the NHS in Scotland does currently.”

They added: “Due to its high cost and inefficiency, hydrogen is unsuitable for most methods of transportation and heating so it is really hard to imagine where this massive hydrogen market is coming from.

“Hydrogen made from fossil fuels is also being used to extend the lifeline of the oil and gas industry in spite of the overwhelming scientific evidence that fossil fuels must be urgently phased out.

“The Scottish Government must stop being distracted by hydrogen and improve its energy strategy so that it focuses on real and much-needed solutions to the climate crisis that will also improve lives like insulating homes, installing heat pumps and public transport run in the public interest.”

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Opposition parties have criticised the "wildly overblown" claimed by the Scottish Government.

Liam Kerr, Scottish Conservative shadow net zero, energy and transport secretary, said: “This is all too typical of the kind of blithe assertions made in the SNP’s draft energy policy.

"Like their unrealistic claims about green jobs – of which only a fraction of their promised total has materialised – they’ve made a wildly overblown claim, backed with little to no evidence, and then they’ll be surprised when yet again they fail to deliver."

He added: “Hydrogen almost certainly has enormous potential. But Scotland’s policy on it needs to be studied, evidenced and planned diligently, with robust scrutiny.

"The SNP, judging by their track record, are incapable of this. Instead we get hot air, when people and businesses want to hear the truth and practical solutions.”

The Scottish Government’s Net Zero Secretary has insisted ministers remain “really confident” about the role hydrogen can play.

Speaking to The Herald, Ms McAllan added: “We will develop it for use here but we have a comparatively small industrial base compared to somewhere like Germany.

“Germany is very keen to see what can be exported from Scotland to them to help them decarbonise.

“So I think that hydrogen is not only critical to what we we've got to do here, but actually it'll be a major export for Scotland into countries throughout Europe.”