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The energy transition, we are constantly told, is a gargantuan task.
Reaching net zero will require all the technologies we can throw at it — solar, wind, grids, batteries, hydrogen, nuclear, carbon capture, electric vehicles and heat pumps — plus more besides.
While there is so much work to be done, and so much uncertainty over the shape and speed of the rollout, does it make sense to ditch one of the potential solutions and narrow our options?
Yes, says the National Infrastructure Commission, which last week recommended that the government should not support the rollout of hydrogen heating. This was met with heated responses from industry and trade unions. The government, which has pledged to decide what to do with heating by 2026, has also been noticeably lukewarm in its reaction.
Hydrogen has a couple of things to recommend it for heating homes. First, it can be made from water and renewable energy. Second, it is, we are told, potentially a straight substitute for natural gas, running through the same pipelines and generating heat through boilers. If clean hydrogen and the infrastructure to deliver it were available at scale, we might be able to switch whole villages at a stroke.
That is a pretty big plus. The alternative, for the 88 per cent of UK households that rely on gas, is heat pumps. Rolling these out requires individual homeowners to make the investment decision to switch to electric heat.
Yet continuing to pursue hydrogen heating has some downsides.
The first is that it is likely more expensive than heat pumps. A lot has been written, including by me, on the magic of heat pumps. These reverse-fridges use electricity from the mains to pump heat from outside into the property, meaning that they deliver 3 kWh for every one that they consume. Conversely, a lot of electricity is lost in converting to hydrogen, which means that only about 0.6 kWh is delivered as heat.
This makes heat pumps five to six times more efficient than hydrogen, the NIC believes. The difference is enough to offset all the associated costs to upgrade the power system. Indeed, their modelling suggests that a system with some hydrogen heating, alongside heat pumps, would be 20 per cent more expensive than one without.
Another objection to heat pumps is that they are hard to install, require extensive renovation and insulation, and that some properties are simply unsuited to them. But this may be overdone. The NIC report suggests that 90 per cent of homes could install one with little to no investment in home improvement. High-temperature pumps would also be able to use existing radiators.
There is also a case to be made that hydrogen heating has missed its moment. It is unlikely to be available at scale until well into the 2030s. Even assuming this can be achieved, it makes little sense to leave the heating sector cooling its heels until that time.
Yet, if households start switching to heat pumps now, and 7mn need to do so by 2035 if we are to meet the sixth carbon budget, the costs of a future hydrogen network will need to be borne by a dwindling number of potential customers.
These points are all arguable, of course. Modelling the energy system is a mug’s game, the costs that we will bear between now and 2050 are likely to be very different from those that we can estimate today. So perhaps that 20 per cent difference in the overall cost of the system should not, by itself, swing the argument.
Most pertinently, heat pumps are barely part of the mix today. Only 8 per cent of households have electric heating, of which the majority will be electric storage heaters or electric boilers, and adoption rates for pumps are slowing. Pinning our hopes of meeting net zero on a rapid rollout seems naive.
Yet, by keeping our options open, we may be slowing their progress further. Homeowners with elderly boilers may be tempted to replace them with a similar model, in the hope that hydrogen might come their way. The government may hold back from extending more support to heat pumps.
That is a problem. There is no perfect solution to decarbonise heating. But in net zero, like in so much else, sometimes biting the bullet and doing the best with what is available may be the best course of action.
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