Using hydrogen in the home would be about four times more dangerous than natural gas, according to a safety assessment conducted on behalf of the UK government.

The report, produced by engineering consultant Arup for the Department for Business Energy & Industrial Strategy’s Hy4Heat programme, found that the annual predicted number of gas explosions in UK homes would more than quadruple if natural gas were to be replaced by hydrogen — rising from nine to 39.

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This would include an average of 25.6 kitchen explosions per year, and 13.8 “whole downstairs explosions”, compared to 5.7 and 3.3 for natural gas, respectively.

At the same time, the predicted number of individuals injured from domestic explosions would rise from 17 to 65, says the study, entitled Safety Assessment: Conclusions Report (Incorporating Quantitative Risk Assessment.

“This is because of the more serious consequences predicted by the [University of] Warwick model for the higher concentration hydrogen explosions,” says the report.

It also found that the installation of two excess flow valves in a property would reduce predicted annual hydrogen home explosions to 26, with 16 injured individuals each year. This is “due to the reduction in frequency of large and very large leaks which have the potential to lead to the worst-case explosions”.

Tom Baxter, a chemical engineering consultant and senior lecturer at the University of Aberdeen, was not impressed. “Is that like buying a car that will crash more often but, because of the safety features, you have the same chance of an injury?” he wrote in LinkedIn. “It doesn’t feel right.”

Michael Liebreich, the influential energy analyst and founder of BloombergNEF, told Recharge in June: “You're not going to have hydrogen in your home for safety reasons. It's just not going to be a thing.”

Hy4Heat is a multi-year project with a mission “to establish if it is technically possible, safe and convenient to replace natural gas (methane) with hydrogen in residential and commercial buildings and gas appliances”.

The UK government is now pushing ahead with domestic hydrogen heating demonstration projects.