Hydrogen in space and hot water heating will be more expensive and less efficient than other clean alternatives in almost all circumstances, according to a review of 32 independent studies into the subject, leading to calls for proponents to “stop the fight” for hydrogen heating.
The peer-review report from energy researcher Jan Rosenow, published in the Joule scientific journal today, expands an 18-strong “study of studies” he compiled earlier this year, and decisively backs up the original list’s conclusions.
The review comes as energy analysts Cornwall Insight warn in a separate analysis that hydrogen heating could almost double the cost of heating a domestic property by the end of the decade, compared to fossil gas.
The cost of using 100% green hydrogen powered by newbuild offshore wind in a UK home would push prices up by 94.7% in 2030 against fossil gas, before declining to a premium of 66.3%, Cornwall Insight calculated.
Not one of the 32 independent studies found that hydrogen was a cost-effective decarbonisation solution for heating compared to heat pumps, solar thermal or district heating — either in terms of energy system costs or consumer costs.
Echoing the earlier analysis, Rosenow, who heads up sustainability think-tank the Regulatory Assistance Project (RAP), reiterated that the relative inefficiencies of electrolysis and the average boiler and the relative efficiency of heat pumps results in a hydrogen boiler requiring five times the energy resources of an air-source heat pump.
Electrolysers swallow around 20% of the feed electricity in the conversion to hydrogen, while boilers lose a further 15% converting to heat. Hydrogen also contains about three times less energy by volume compared to natural gas, so higher quantities are needed to produce the same amount of heat. Plus, due to the smaller molecules, roughly three times as much energy would also be required to pump hydrogen into homes and business compared to natural gas, and energy is also required to compress the H2, further reducing the round-trip efficiency.
Any cost reductions achieved by green hydrogen producers on account of cheaper renewable electricity will be more than matched by alternatives that are directly electrified, the report noted.
And the cost profile does not improve for blue hydrogen, according to Cornwall Insight. The premium on blue hydrogen made from fossil gas and carbon capture and storage (CCS) would peak at 78.7% in 2039 — nearly ten years later than offshore wind-powered green hydrogen — at which point it would become more expensive than green H2.
What is more, the one study in the Joule review that examined the lifecycle environmental impact of hydrogen boilers against other alternatives found that H2 burners have the highest environmental impacts in all cases.
“Hydrogen for heating necessitates more energy supply infrastructure, uses more resources and requires more land,” the peer-reviewed report noted, adding: “Hydrogen use for domestic heating is less economic, less efficient, more resource intensive, and associated with larger environmental impacts.”
However, the review did acknowledge some evidence supporting the use of hydrogen heating in certain specific circumstances. In areas where the cost of grid upgrades are particularly high, for example, a so-called “hybrid hydrogen heat pump” could save power at peak times by burning hydrogen for heat.
And where expansive hydrogen infrastructure is already in place to serve industry, H2 heating might prove viable, the report said, but warned that the evidence is insufficient to draw a conclusion either way.
The report was welcomed by Bloomberg New Energy Finance founder Michael Liebreich who last week —in a characteristic turn of phrase — tweeted that hydrogen heating would not “be a thing”.
“No serious analysis has hydrogen playing more than a marginal role in the future of space heating,” he said. “We need to get Europe's heating systems off natural gas, and we need to do it without further delay. It's time to stop the fight: the judges are unanimous and the winners are district heating, heat pumps and electrification.”
Rosenow called for governments to consider the evidence before committing public funds to hydrogen heating, and focus instead on decarbonising the existing hydrogen industry.
“Using hydrogen for heating may sound attractive at first glance,” he said. “However, all of the independent research on this topic comes to the same conclusion: heating with hydrogen is a lot less efficient and more expensive than alternatives such as heat pumps, district heating and solar thermal.”
He added: “Rather than hoping for hydrogen to eventually be able to replace fossil gas used for heating our buildings we should focus on speeding up the roll-out of energy efficiency and heat pumps, technologies consistently identified as critical for reducing carbon emissions from buildings.”
All of this appears to be falling on deaf ears in the UK, which is throwing its weight behind hydrogen heating and blue hydrogen (made with fossil gas and carbon capture and storage) — at least partly due to the lobbying efforts of local gas distributors such as Cadent and SGN.
The government, which recently appointed a new prime minister, Liz Truss, vowed to accelerate the delivery of the Hynet and East Coast Cluster blue H2 projects in its emergency budget on Friday.
And newly minted energy secretary and fossil-fuel enthusiast Jacob Rees-Mogg is advocating for curtailed wind and solar power to be used to make hydrogen for heating.
“I think hydrogen is ultimately the silver bullet,” he told Parliament last week. “We create it from renewable sources, because we have the wind power when people are not drawing on the electricity system; we use it as an effective battery and it can then, with some adjustments, be piped through to people’s houses to heat them during the winter.”
The economic case for using curtailed wind and solar to power electrolysers is thin at best. The low utilisation rate — estimated to be around 10% by the International Renewable Energy Agency — would not produce enough hydrogen to make the investment worthwhile for an H2 producer.
For the UK, which has more installed wind capacity than solar, the curtailment level drops to just over 3% on average, and Cornwall Insight noted that powering electrolysers with curtailed renewable energy would not produce anywhere near enough H2 to decarbonise the country’s heating.
There are 120 paid hydrogen lobbyists operating in the UK parliament at present, according to the MCS Charitable Foundation, which commissioned the heating report from Cornwall Insight.
That report follows a similar conclusion from campaign group Global Witness, which estimated the use of hydrogen in heating would double European energy bills by 2050.