This necessity is a cornerstone of civilization. It’s more important than transport, electricity and even—shock horror—the internet. It accounts for half of the energy we use globally.
So what is it?
It’s heat. And if you didn’t guess correctly, that’s okay: in the global fight against climate change, our need for heat is often overlooked. But how do we produce enough of it without also warming the planet?
Recognizing this conundrum, last week the U.K.’s Committee on Climate Change, which reports on Britain’s decarbonization progress, emphasized renewable heat as a top priority in preparing for the future. The authoritative body recommended that the Treasury should directly support renewable heat, singling out the installation of heat pumps and heat networks as an “infrastructure priority.”
Now, a U.K. pressure movement is challenging the government to take heat more seriously. According to the Pump It Up campaign, the government is ending a financial support mechanism for large-scale renewable heat schemes, effectively banning the implementation of such projects for towns, schools and industry. This move, the campaign says, contributes to the risk of Britain failing to meet its own climate targets.
But what makes renewable heat so important—and why is it so difficult to achieve?
“Heat is an intrinsic energy service that is central to most people’s lives,” says Richard Lowes, a research fellow and lecturer at the University of Exeter’s Energy Policy Group. “Everyone needs hot water for sanitation; you can’t cook without it—and one of the biggest issues is people don’t appreciate that.”
The fundamental need for heat means it comprises a huge chunk of our energy usage. And while coal and oil account for a proportion of the fuels used, by far the biggest share comes from the burning of gas. All told, some 30% of man-made emissions come from producing heat.
“About half the energy we use goes towards heating, and most of that comes from fossil fuels,” Lowes says. “So heat is effectively half of the problem.”
But progress on decarbonizing heat has been slow. It is likely that the U.K. has missed its target, set way back in 2009, of generating 12% of heat from renewable sources by 2020. The government’s own figures show that in 2018, just 7.2% of heating was renewable.
One explanation for the sluggish rate of change, Lowes suggests, comes down to image.
“Heat’s never had that ‘eco-bling’ factor,” he says. “Unlike e-bikes or Teslas, most people try to hide their boiler; they have ugly radiators they don’t like. A lot of people will have thought of switching their cars to electric, but will never have considered switching their heating from gas or oil.”
Furthermore, a lack of regulation and government support has meant that district heating, in which a central facility generates and distribute hot water to hundreds of homes and businesses, has failed to take off in the U.K., while the practice is booming in Europe. The current target is to have a modest 17% of British home heating needs met by district heating by 2050. By comparison, a whopping 64% of homes in nearby Denmark are heated via district heating—and much of that capacity is being converted to renewable heat using heat pumps.
But according to the Pump It Up campaign, which is supported by a range of industry and academic groups, the government’s decision to end its renewable heat incentive (RHI)—a subsidy for large-scale renewable heat schemes—could prevent such projects from being built.
The policy under consultation until July 7th by the U.K. Department for Business, Energy and Industrial Strategy proposes a 45 kilowatt capacity limit for schemes under the RHI. For smaller installations, the RHI will be replaced by a system of grants. Campaigners say this will effectively rule out large, district and institutional-level heat pumps of the sort needed to decarbonize towns, schools, agriculture and industry, with the low price of natural gas making green alternatives uncompetitive.
“The government is saying ‘we’re going to stop providing support for large heat pumps,’” says Dave Pearson, a spokesperson for the Pump it Up campaign and director of Glasgow firm Star Renewable Energy. “They say they’re going to try and create some other sort of mechanism for clean heat networks—but they seem to be forgetting that the more important challenge is to decarbonize existing buildings. That won’t happen without buildings being forced to reappraise the polluting effect of burning gas.”
The withdrawal of the subsidy, Pearson says, will mean fewer renewable heat projects like that at Queen’s Quay in Glasgow. Here, the local council is developing a pioneering district heating network using a system of heat pumps that draw heat from the river Clyde to an energy center, which in turn pumps hot water to local homes and businesses. As many as 1,400 homes will be included in the network, along with a local college, leisure center and hotels.
“Large, river source heat pumps are the gold standard that all other renewable heat techniques should be measured against, ultimately to be found wanting,” Pearson says. Such projects are “viable now, durable and don’t compromise air quality, and being based on a plentiful water resource offer as low a cost as possible whilst creating significant employment opportunities.”
Just what makes heat pumps so attractive as an option for decarbonizing heat?
Powered by electricity, heat pumps use differences in the temperature of water, air or the ground to activate a cycle similar to a refrigerator but in reverse, releasing heat into a space. They are considered to be one of the most efficient ways of heating a space: studies show heat pumps can have a coefficiency of performance (COP) of 4, meaning that for every 1 kilowatt of energy used, 4 kilowatts of thermal energy are produced. This makes them massively more efficient than typical gas or oil-fueled boilers, which generally have a COP of less than 1. And when the electricity used to power heat pumps comes from renewable sources, both direct and indirect emissions are essentially eliminated.
“Heat pumps are our preferred technology because they are clean,” says Nigel Aylwin-Foster, also with the Pump It Up campaign, and sales and marketing director for ReEnergise Projects, which develops low-carbon heating for schools. “With heat pumps there are no emissions on site, and if you power your heat pump with grid power from renewable energy, we’re talking about completely clean heat.”
But Aylwin-Foster says that even a small school has power needs in excess of 100 kilowatts—far greater than the government’s proposed 45 kilowatt limit.
As a result, some independent schools in England that had been planning to install heat pumps are now having to think again. One such school is St. George’s Weybridge in Surrey, an independent school with about 1,600 students. St. George’s was planning two ground source heat pumps, one on each of the school’s two campuses.
“We have already maximized our uptake of solar PV and really wanted to make a big reduction in our carbon footprint through reducing gas consumption, says Greg Cole, St. George’s bursar. “The timing was right, financially, following the completion of a major new sport and activity facility, and the increase in momentum around sustainability meant we had the support of our community.”
Cole says the ground source heat pumps would have resulted in an immediate 70% reduction in the school’s use of gas, rising to an eventual 90% reduction. Now, the two projects could be nixed.
“The RHI makes the projects affordable—nearly cost neutral—for us over a 20-year term,” Cole says. “Without RHI, the governors are very unlikely to be financially persuaded.”
To save the projects, Cole says an extension of the RHI, or an equivalent mechanism, would be required.
So what’s the solution?
Dave Pearson suggests one solution to the impasse would be to use revenues from the Climate Change Levy—a U.K. tax on non-domestic energy users—to continue the renewable heat incentive, thus continuing to support retrofit projects. “Why not use the revenues to continue to support these schemes via the RHI until gas is phased out?” Pearson asks.
Richard Lowes says the problem of decarbonizing heat inevitably comes back to the cost factor, and that if the government is serious about its climate goals, renewable heat will require cohesive support.
“If the RHI had deployed the number of heat pumps it was supposed to, we’d be in a place now where we’d have a decent sized low-carbon heat market,” he says. One way to foster a functioning market, Lowes says, could be a carbon tax, noting that the tax on petroleum for vehicles is much higher than it is for natural gas. But this solution, he points out, could end up harming families suffering “fuel poverty”—that is to say, the millions of low-income British citizens being pushed into poverty in part by high heating bills.
“The point is that gas is cheaper than electricity, but the U.K. government has loaded more various policy costs onto electricity, such as a carbon tax and renewables subsidies, while gas has escaped these costs,” Lowes says. “This makes the imbalance worse and stacks the economics in favor of gas—so why should customers switch?”
The way forward for heat decarbonization is uncertain. But if the U.K. is to achieve its legally binding target of becoming carbon neutral by 2050, time is running out.
“It’s a horrible problem,” Lowes concedes. “I’ve been working on this for 10 years, and nothing’s happened. We’ve got 30 years to go, and every year that goes past, that goal becomes more and more difficult to meet.”