UK weighs up hydrogen’s potential for heating homes

Across Europe, natural gas remains a core source of energy in homes and industry. But pressure to meet carbon reduction targets by substituting natural gas with less polluting hydrogen is creating stark contrasts in policy and provoking political debate.

In Britain, the government is considering plans to blend hydrogen with natural gas in order to deliver a less polluting combustible fuel to the majority of homes for the foreseeable future. Some 20 per cent of all UK carbon emissions are from residential use — mainly natural gas used for heating and cooking.

Later this year, UK energy secretary Grant Shapps will decide whether to start introducing a mix of up to 20 per cent hydrogen into domestic national gas supplies in the second half of this decade, a blend that is generally considered safe for distributing hydrogen through existing networks.

Beyond that, the UK is looking at proposals for all newly installed domestic boilers to be “hydrogen-ready” — capable of operating on full hydrogen — from 2026.

Along with helping to deliver cleaner combustible fuel in homes, this stepping stone approach could also moderate the strain placed on future electricity supply by the anticipated adoption of heat pumps and electrical heating in UK homes — 85 per cent of which are currently heated by gas boilers.

However, this UK strategy is at odds with the approach being pursued in Germany. There, proposals to largely ban gas boilers from new and replacement heating systems from next year were unveiled in April, and have split the ruling coalition.

Proponents of the new German laws are putting most of their faith in heat pumps — generally seen as the leading short-term alternative to natural gas for home heating — rather than any rapid switch to blended or ‘pure’ green hydrogen, which is produced by using renewable energy to split water molecules.

Jan Rosenow, European programme director at RAP, an independent energy think-tank, is also sceptical about green hydrogen’s suitability for home heating — although he does see the gas as key to decarbonising the wider power supply.

“The good news for the green hydrogen industry is we need lots of it,” he says. “But the priority should be where it’s clear that it’s a good use of hydrogen.”

His review of 32 studies worldwide, published last October, concluded that “compared to other alternatives, such as heat pumps, solar thermal and district heating, hydrogen use for domestic heating [was] less economic, less efficient, more resource intensive, and associated with larger environmental impact”.

Instead, he advocates prioritising green hydrogen as a substitute for the large volumes of “dirty” hydrogen derived from fossil fuels in existing industrial processes. These include fertiliser production and heavy industries such as steel and cement making.

He also points to seasonal energy storage — converting surplus renewable solar and wind power via hydrolysis into green hydrogen that can later be burnt to generate electricity. While this involves large energy losses, Rosenow maintains that “for seasonal storage, it’s not that bad”.

UK gas companies are pushing ahead on feasibility trials that anticipate a growing fuel stock role for both green and blue hydrogen — where carbon capture and storage is used to mitigate the pollution caused by its conversion from natural gas.

Regional gas distributor Cadent is hoping to run a government-backed local trial of 100 per cent-hydrogen domestic heating in Whitby in Cheshire, while Northern Gas Networks is seeking to run an equivalent test in Redcar in north-east England, starting in 2025.

Cadent has already led a trial called HyDeploy with Keele University, which demonstrated that a 20 per cent blend of hydrogen in natural gas can be used to heat homes and buildings, with the potential to cut carbon emissions without changing gas appliances or pipework.

Jake Tudge, corporate affairs director at National Gas, which operates the backbone of the UK gas network, estimates that half of UK homes, if properly insulated, could be suitable for heat pumps. But he insists other alternatives to natural gas — including hydrogen — will be required to heat the remaining housing stock.

He suggests a requirement to install “hydrogen-ready” boilers when replacing defunct units from 2026 on could result in a “no regret” investment in houses not suited to heat pump installation — as long as hydrogen-only units reach price parity with conventional boilers.

Industry estimates put the cost of hydrogen-ready boilers at around £2,000, compared with £9,000 to £15,000 for an air-source heat pump.

According to a UK parliamentary report published in December, there is no clear consensus on the “optimum mix” for deploying hydrogen, heat pumps, heat networks and other hybrid solutions to decarbonise heating.

However, on cold, dark and still winter days, when wind and solar power stalls, stored green or blue hydrogen could be substituted for natural gas to bolster the supply of low-carbon electricity. This will require a significant reconfiguration of gas supply networks, though, and the retrofitting of gas turbines in power stations.

“We need a huge amount of power back-up, using hydrogen storage and hydrogen gas turbines and, if you want to decarbonise industry, hydrogen has an important role for those that cannot electrify,” says Tudge. “Hydrogen has a massive storage role in the system.”

James Earl, director of gas at the UK’s Energy Networks Association, which represents the biggest electricity and gas distributors in the country, argues that green and blue hydrogen will be needed to meet net zero ambitions.

“Looking ahead to 2050, there is no way we can do that without some form of ‘green’ gas in the mix,” he says. “We are all going to have to embrace change — whether that’s through a move to hydrogen, through increased electrification or through a combination.”

Tudge at National Gas agrees: “We need to use every tool in the box.”