Thursday, April 18, 2024
Heating Your Home

Hydrogen or heat pumps: How will we heat our homes in the future?

In the neighbourhood of Whitby in Ellesmere Port, Cheshire, residents are grappling with a question that many more of us will have to ask in the coming years: how should we heat our homes if we’re no longer allowed gas boilers?

The neighbourhood is one of two sites, the other being Redcar in North Yorkshire, which the government may select next year to become the country’s first “hydrogen village”.

If Whitby is selected, then Cadent, the gas distribution network that would be running the trial, will offer residents a choice of replacing their gas boiler either with one that runs on hydrogen, or with a heat pump. Cadent would pay for either, but after it has repurposed the neighbourhood’s pipes to deliver hydrogen, residents would not be able to return to gas.

The trial will inform the government’s decision, in 2026, as to whether hydrogen, which releases no carbon dioxide when burnt, will have a substantial role in reducing the greenhouse gas emissions that come from heating the country’s homes. Those emissions account for about 14 per cent of the country’s total — thanks to our 23 million gas boilers.

Under government plans, no homes will be built with gas boilers from 2025, and their sale will be banned from 2035. But if domestic heating is to be decarbonised, it won’t be enough merely to stop gas boilers being installed. We’ll also have to replace those we already use.

But what will we replace them with? Would it be economical and practical to deliver hydrogen through the existing gas network? Or could we rely on heat pumps and electric boilers to do the job instead?

These are questions that residents of Whitby find themselves unexpectedly having to ponder. Since the beginning of the trial, more than 900 residents have joined a Facebook group where they share experts’ opinions on the future of home heating.

The group was set up by Kate Grannell, a resident, who believed Cadent, with its vested interest in maintaining the use of its pipes, was manipulating her community into choosing hydrogen over heat pumps. She was initially in favour of the trial, thinking “that sounds great, I want to help fix the planet”, but now believes that the two Cadent employees who told her about the merits of hydrogen “sold it to me on a dream and a whim”.

She worries that Cadent might be leading her community up a dead end, towards a technology that heat pumps could render superfluous.

Yet Cadent’s director of strategy Angela Needle thinks it would be a mistake to pit one technology against the other. She sees them as “complementary”, and expects heat pumps to be “the dominant technology”, servicing new-builds and spacious, well-insulated houses.

She also asserts that not all homes will be suitable for heat pumps, because “they take up quite a bit of space”, while adding that they are expensive — an air source pump costs between £7,000 and £13,000, according to the website heatpumpchooser.com — whereas boiler manufacturers have pledged that hydrogen boilers will be no more expensive than the ones currently in use. She also says that installing a heat pump is often more inconvenient than swapping a natural gas one for a hydrogen boiler, because “you might have to get new radiators”.

For these reasons, Needle expects that “between 30 and 50 per cent” of homes will be heated by hydrogen in the decades to come, compared with 80 per cent now heated by gas. It’s not that it would be impossible to install heat pumps in these smaller, less well-insulated homes, she argues, it’s just that it might not be economical to do so.

Needle’s estimate is roughly in line with a report produced by researchers at Leeds Beckett University in partnership with the Energy and Utilities Alliance, a trade association of which Cadent is a part. The report found that only seven to ten million British homes are suitable for heat pumps, while three to four million could be made so with improvements such as cavity wall insulation. It found that between eight and 12 million homes were rendered unsuitable by “a lack of exterior space and/or the thermal properties of the building fabric”.

The report found a variety of types and ages of property were unsuitable for heat pumps, including prewar terraces and flats. These findings are substantially more pessimistic than those of a government-backed study published last December, which found that all housing types are suitable for heat pumps, including Victorian terraces and prewar semis.

It is one of many recent studies that have suggested hydrogen might play a minor role in heating, if any at all. This month the International Energy Agency said it expected the fuel to play a “negligible” role.

This was also the conclusion the energy researcher Jan Rosenow came to, after reviewing all 32 independent studies of heating homes with hydrogen. “Not a single one of them says hydrogen is going to be cheaper and more cost-effective than deploying the other solutions, like heat pumps and district heating,” Rosenow says.

One of these studies showed that by 2050 hydrogen boilers could be between two and three times more expensive to run than heat pumps, which are already cheaper to run than boilers thanks to this year’s increased gas prices.

Rosenow explains that hydrogen boilers will always cost more to run than heat pumps because they are less efficient. The only carbon-free way to make hydrogen is to run a renewably generated current through water, a process that produces about 0.7 units of hydrogen energy for every one unit of electricity.

Heat pumps, by contrast, produce between three and four units of heat for every one unit of electricity. This means that the same amount of electricity can generate about five times as much heat via a heat pump as via the production and combustion of hydrogen.

Rosenow is also dismissive of the idea that there are certain homes where only hydrogen could replace natural gas. “Electric boilers are less efficient than heat pumps but they can replace a gas boiler and they look just the same,” he says.

He has been advising the residents of Whitby alongside Michael Liebreich, the founder of Bloomberg New Energy Finance. Liebreich disputes Needle’s suggestion that residents will find hydrogen boilers more convenient to install than heat pumps.

Whereas heat pumps can be installed one house at a time, the layout of gas pipes means that entire neighbourhoods will have to be switched to hydrogen in one go. Liebreich points out that, when the natural gas supply is turned off in preparation for the switch, “those homes that are refusing [to get a hydrogen boiler], and those who haven’t had them installed yet — those people are cold.

“Those old people are on Channel 4 News wearing duvets because they’ve got no heating, no cooking. That’s the reality of what’s coming.”

Liebreich believes the gas distribution networks are playing down this difficulty because the uptake of hydrogen “is existential for them. They don’t have a product B.”

He adds: “What the future looks like, in my view, is a number of years of confusion and a lot of silliness, and then finally we’ll get our act together and go with heat pumps.”