As the future of home heating takes shape, is hydrogen’s potential waning?
Heat pumps are winning the race to replace gas but critics fear they are unsuitable for UK housing, reports
David Martin ditched the oil-fired heating system at his threebedroom bungalow in rural west Wales three years ago. The 74-year-old widower installed a heat pump and solar panels instead, and has never looked back. He says his energy costs were £347 in 2022, once sales of electricity from his solar panels were taken into account, with his bungalow “never allowed to go cold”.
Hundreds of miles east of him, near Peterborough, 70-year-old Sara Hawkes had a very different experience with the heat pump she had installed in 2018. “In prolonged cold weather, mine ices up and stops the blades from turning,” she says.
The two households are early movers in a growing shift up and down the country as the net-zero push reaches inside the home.
Over the next few decades, around 23m UK homes will be asked to ditch their gas boiler for a cleaner alternative as Britain tries to cut its carbon emissions to net zero by 2050.
What will replace them has been the subject of fierce debate, with industry divided over the merits and pitfalls of the front-runners – hydrogen or heat pumps. Recent developments have led to heat pumps gaining ground, with hydrogen still a long way off from being deployed in people’s homes.
Hydrogen-ready boilers are not yet on the market and a growing body of research has raised questions about its usefulness for mass heating.
As the future of domestic heating starts to take shape, is hydrogen’s potential role diminishing? And what does this mean for households who are looking to ditch their old gas boilers? “I think heat pumps are definitely in the ‘box seat’, says Guy Newey, chief executive at the government-backed Energy Systems Catapult.
“We’ve got to make sure that whatever technology is installed in people’s homes, people want it and welcome it. Consumers have a veto on net zero.”
Cutting the carbon footprint
Heating UK homes is a major source of carbon emissions, accounting for about 14pc of the country’s carbon footprint.
None of the gas boilers’ potential replacements are without challenges at a system-wide level, however.
Heat pumps are highly efficient, drawing warmth from the outside air, to produce more energy than they use to run. They are powered by electricity, more of which in the future will be generated from green sources such as the wind and solar.
However, that puts a strain on the grid, which will already be trying to cope with increased demand from millions of electric cars. Studies suggest heat pumps more than double a household’s annual electricity consumption – and will add to surges in demand at peak times.
The Government is considering introducing short, randomised delays to when appliances, including heat pumps, switch on in order to lessen the pressure on electricity grids.
Hydrogen, on the other hand, which does not produce carbon emissions when burnt, can be produced at any time, is transported through the existing gas network, and used by the consumer in the same way as natural gas. The gas is currently expensive and difficult to produce cleanly, however, potentially eating up vast amounts of clean electricity.
Many experts believe it will be prioritised in areas that have no other options for cutting carbon emissions, such as some parts of heavy industry. Dr Jan Rosenow, an energy efficiency expert at the University of Sussex, recently reviewed 32 “independent” studies, and says they indicate hydrogen for domestic heating is less economic and efficient than heat pumps and other sources. He says it “takes about five times more electricity to heat a home with hydrogen than it takes to heat the same home with an efficient heat pump, either individually or as part of a district heating”.
Meanwhile, households are starting to engage with heat pumps. More than 40,000 were installed last year – albeit a fraction of the 1.7m new gas boilers put into houses.
The Government’s confidence in heat pumps appears to be increasing, spurred by an Energy Systems Catapult study earlier this year that reported better efficiency than expected.
Ministers are pressing ahead with plans to force boiler makers to produce a certain number of heat pumps, and to move levies off electricity bills.
Grant Shapps, the Energy Secretary, is planning to install a heat pump.
The Government does not intend to decide on its strategy for hydrogen in home heating until 2026, after trials have been finished. One of those trials has had a troubled start. Cadent Gas has had to promise households in Whitby and Ellesmere Port that they can opt-out and stick with natural gas after uproar among residents at being forced to ditch their boilers.
Dr Angela Needle, director of strategy at Cadent Gas, says it is still too early to determine hydrogen’s role.
“We expect the future energy system to have about 30pc hydrogen in it,” she says. “The amount of homes that end up having hydrogen is quite difficult to say – it will depend on whether there is enough hydrogen and how much of the gas network is converted.”
As heat pumps gather pace there is a risk of choices narrowing, however. Gas network owners will, presumably, need a certain number of customers to make a pipeline commercially viable.
“There may be some streets where you say, this is a heat pump street, and we end up looking at decommissioning at some point in the future,” says Dr Needle. “But we are a long way away from that.”
Questioning the conclusions that can be drawn from the academic research studied by Dr Rosenow, she asked: “Do they [the studies] cover the whole value chain of production of the energy to consumption? Are they relevant for the UK energy system?”
With so much yet to play for, investors are still hedging their bets. Brookfield Asset Management, the $800bn (£645bn) asset manager chaired by Mark Carney, the former Bank of England governor, paid £4bn last year for the UK home repairs and boiler installer HomeServe.
Through its Thermondo subsidiary, it installed hundreds of heat pumps in Germany last year. It also owns a stake in UK gas pipeline owner Scotia Gas Networks.
“We think that there’s a range of decarbonisation technologies which will be critical to reduce household emissions in a cost-effective way,” says Louis Socha, who leads on Brookfield’s strategy for residential decarbonisation in Europe.
“There will be cases for hydrogen; it obviously has benefits. But also we think there will be millions of homes that will be retrofitted to heat pumps over the long term.
“We see benefits to both – we want to remain agnostic. We’re focused on providing consumers with the right package.”
For households wanting to ditch their gas boiler right now, however, the slow progress on hydrogen means there is little choice other than a heat pump.
“As you can imagine I’m very happy,” says Mr Martin. “I really feel for the people who have been struggling this winter.”
‘It takes five times more electricity to heat a home with hydrogen than it takes with an efficient heat pump’