Hydrogen boilers could cause four times as many explosions as gas

Hydrogen for home heating could cause four times as many explosions and injuries than gas boilers, according to a government-backed study.

Hydrogen is being trialled at test sites across the UK to assess whether it can safely be used as a potential green replacement for natural gas to heat homes.

But a safety assessment carried out by consultants Arup on behalf of the business department found that hydrogen in homes could cause 65 injuries or fatalities a year, and 39 explosions in the kitchen or entire ground floor, compared to 17 individuals injured and nine explosions for natural gas.

Hydrogen is lighter and more flammable than natural gas, which is mostly methane. It has never been used in a gas grid supply to homes.

Commenting on the study, Dr Richard Lowes, an energy expert at the University of Exeter, said hydrogen was “deeply uncertain in many ways”.

“Hydrogen is quite simply more explosive than the current gas in our pipes and therefore, more likely to cause damage if it goes wrong,” he said.

The risk can be mitigated by installing extra equipment, known as excess flow valves, in the pipe network, according to the study.

The Government is due to shortly set out its plans for replacing gas boilers in order to meet the country’s carbon reduction targets, alongside its plans for hydrogen use within the economy.

Ministers are hoping hydrogen could provide a more familiar replacement to gas boilers, compared to the alternative heat pumps, which run on electricity.

The safety assessment was made weeks before Kwasi Kwarteng, the Business Secretary, suggested hydrogen could be used to replace a majority of gas boilers, depending on the results of trials.

The Government plans to unveil a hydrogen-powered town by 2030, likely to be near one of the UK’s new industrial clusters, where homes and transport could run on the gas.

“We need to move way faster than that with known technologies such as energy efficiency, heat pumps and heat networks,” said Mr Lowes. “We will likely have breached the 1.5 degrees Celsius warming target by the time any potential hydrogen conversions could have been carried out.”

Industry estimates put the cost of hydrogen for home heating at around three times that of natural gas.

Converting home heating systems to carry hydrogen will require new smart meters which may have to be moved outside, and is likely to require bigger pipes.

There is also as yet no known mechanism for moving hydrogen, which is much lighter than methane, around the existing gas grid.

The study points out that the move to hydrogen would eliminate the risk of carbon monoxide poisoning, which kills around 60 people every year.