In October last year, a peer-reveiewed study of independent studies into decarbonised heating was published in the scientific journal Joule, declaring that every single one — all 32 of them — concluded that hydrogen would not play a significant role in zero-carbon heating.

Hydrogen: hype, hope and the hard truths around its role in the energy transition
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The author of that “meta-analysis”, energy researcher Jan Rosenow, now says that five more studies can be added to the list — as gas distributors, boiler makers and their supporters continue to argue that H2 will play an important role in heating our homes in the future.

  • A study published in the International Journal of Hydrogen Energy in January by academics at Denmark’s Aalborg University found that hydrogen for heating would be more expensive than electrification and district heating.
  • Another paper published in the same issue, authored by a trio at Berlin Technical University, found that its hydrogen scenario would be four times more expensive than its electrification scenario.
  • The next study, from Swiss university ETH Zürich, published in the scientific journal Energy Conversion and Management, concluded that green H2 heating in the EU would be two to three times more expensive than electric options.
  • An analysis published in December in the journal Energy and Buildings by engineers at the University of Warwick in England, which used the UK as a case study found that hydrogen would only play a niche role in heating in cost-optimisation scenarios.
  • A “working paper” from the Fraunhofer Institute for Systems and Innovation Research in Germany found that demand for hydrogen in heating would be almost zero, even when available at low prices.

The simple fact underpinning the findings is that green hydrogen boilers would require five to six times more renewable energy to produce the same amount of heat as electric heat pumps — and the prospect of building five to six times more wind turbines or solar panels — when the world still needs to decarbonise most of its electricity production — is not an attractive one.

The gas distributors and boiler makers argue that power grids will not be able cope with the demand if all homes were heated by electricity in winter — a period when there is little solar power available and winds often die down.

They also argue that the grids cannot absorb all the wind and solar power coming onto the networks at sunny and/or windy periods, so that excess renewable electricity should therefore be used to produce green hydrogen, which can be stored indefinitely and used whenever required. And the amounts of excess wind and solar power will only grow as more turbines and PV panels are added to grids.

Angela Needle, head of strategy at fossil gas distributor Cadent, which is leading plans for a fiercely opposed hydrogen heating trial in northwest England, told a public meeting on Tuesday: “We could be using [the £1bn ($1.2bn) the UK spends each year on curtailed wind energy] to make hydrogen to heat your homes using pipes that already exist that we know can transport hydrogen.”

The counter argument is that using electrolysers only occasionally and storing hydrogen for long periods of time will result in very expensive H2, and, in any case, electricity can be stored using batteries and other technologies. And if green hydrogen could be produced from excess power, the world would be better off if this was used to decarbonise sectors such as fertilisers, where there are no alternative green options.

When questioned at the public meeting about the 32 independent studies, Needle replied that only seven of them were carried out in the UK.

“Of those seven, half of them do talk about some role for hydrogen, so we’re not talking about it being either heat pumps or hydrogen,” she said. “We’re really talking about understanding why we need a bit of both.”

Rosenow responded to this comment on LinkedIn, saying: “Some studies see a very small niche role for hydrogen heating but none identified hydrogen for heating as a significant contributor to heat decarbonisation in the buildings space.”

Of course, blue hydrogen made from fossil gas with carbon capture and storage could be used instead of green H2, and that could be produced in massive amounts, with no dependence on variable sunshine and winds. But due to the much lower energy density by volume of hydrogen compared to natural gas, three times as much gas would be required to produce the same amount of heat, effectively tripling already expensive heating costs.

Another argument in favour of hydrogen boilers is that they will be cheaper to buy and install than heat pumps, with some H2 heating advocates repeating long-debunked claims about the more efficient electric option, such as that heat pumps will not work in old, draughty homes or that they do not work in very cold weather.

In fact, heat pump sales are higher in Europe’s coldest countries than the rest of the EU, with Norway, Sweden and Finland leading the way.

Heat pumps may cost more than gas boilers right now, but that’s mainly because they are not yet benefitting from economies of scale — there is nothing inherently expensive a heat pump, which is basically a fridge in reverse.