Why are we talking about hydrogen boilers?

 

Hydrogen is an incredibly inefficient way to heat your home compared with heat pumps.  Heat pumps move about 4 times as much energy in the form of heat as the electrical energy they consume.  With hydrogen boilers the heat is created from chemical energy rather than moved and so there's no such upscaling.  In fact it's worse than that since the hydrogen has to be created in the first place and if you're creating it from renewable electricity about a third is wasted.

Despite the horrendous waste, hydrogen boilers may have a role.  Heat pumps require an insulated hot water tank and many houses, especially in the UK, will not have space for an airing cupboard.  So perhaps the solution will be to install heat pumps where-ever possible and then use the much-less efficient hydrogen boilers to mop up the rest.  The risk, however, is that the government's enthusiasm for Hydrogen will slow down the decarbonisation of our heating sector.

We are in a deadly race, with only a few years worth of carbon budget left before 1.5C becomes a certainty.  This requires global emissions to at least halve by 2030 and reduce to virtually zero by 2040.  If we had more green electricity than we knew what to do with then it would not be a problem installing a hydrogen boiler where a heat pump would do the job.  But we haven't yet decarbonised our electricity grid, and demand is due to soar as EVs(*) come online.  In this context hyping hydrogen is extremely dangerous.  If we install hydrogen boilers where we could use heat pumps we'll need to wait far longer before we decarbonise because those boilers need 6x as many wind farms.  And if we encourage people to wait for a hydrogen distribution network to be built before changing their boiler, the start of the decarbonisation process will be delayed by many years.

It's mad.  Every scientist and every engineer says it's mad.  So why are so many governments pushing this solution?  The answer may lie in the fact that fossil fuel companies are pushing the hydrogen economy hard and have reportedly spent nearly 60 million Euros lobbying Brussels for it. But why would these companies be lobbying for hydrogen?  The answer is probably twofold:

1. It's going to be a slow process rolling out the hydrogen network and this will buy them several more decades of the status quo
2. Most hydrogen (around 99%) actually comes from natural gas.

Yes, hydrogen is not (usually) green.  Green hydrogen is very expensive to make and involves electrolysis of water, whereas most hydrogen comes from a methane feedstock which is easier to use.  Unfortunately this releases CO2 - more, in fact, than if you just burned the gas for heat as a result of the inefficiency of the process.  Most of this methane-generated hydrogen is "grey" meaning that the CO2 is just released into the atmosphere, with a tiny fraction being "blue" meaning that the carbon is captured using a process that no-one has managed to scale.

So, even when we do eventually get our shiny new hydrogen boilers (and hydrogen cars) they will likely do more damage to the climate than what we have now.  And the fossil fuel companies will be able to play for even more time while they promise us their hydrogen will slowly change from grey to green or blue.

If we were driven solely by a desire to avoid a climate catastrophe (which sounds like a sensible approach) then we would roll out heat pumps as fast as we could everywhere we could, while growing our renewable electricity supply.  Only when we have more green electricity than we need should we start using it to make hydrogen for those homes where heat pumps can't be installed.

POSTSCRIPT

One week after posting the above I saw the following article in Private Eye in which the author appears to have completely fallen for the PR surrounding the idea of hydrogen heating:

Hydrogen hype

OLD Sparky writes: On the path to "net zero carbon" we'll be hearing a lot about converting large parts of our gas system from fossil-fuel natural gas to hydrogen: it's transportable, storable, burns well, emits no CO2 and can be generated sustainably. The practical problems, notably for residential use, are legion; but the same is true of any alternative to gas. On this knotty issue, it's revealing to follow the money.

Hydrogen is easy to scorn on several grounds (cost, energy efficiency, safety); and many do. The obvious suspects (National Grid, the nuclear industry) have strong vested interests in converting gas heating to electricity instead. Some critics assert that hydrogen "hype" is simply the wicked gas industry trying to save its bacon. Others are just technically illiterate.

In energy terms, the amount of gas used for heating and cooking exceeds the total consumption of electricity for all uses-on cold days, by a significant multiple. The trouble for promoters of electricity is that more than doubling the capacity of the entire power system to replace gas would present significant challenges of its own: electrifying transport is difficult enough. But the only outright alternative technology being mooted to replace in homes is heat pumps, wholesale conversion to which also comes with big problems, not not least the huge cost to homeowners, even where it's feasible. How to adjudicate between hydrogen, electrification and heat pumps, three seriously problematic zero-carbon strategies? One clue may be to follow the money.

Ever since decarbonisation started, companies with big ideas have queued up for immense public bungs, government guarantees and favourable regulatory diktats - including the electrifiers and the heat-pump merchants. With hydrogen, in stark contrast, an astonishing amount of global effort is proceeding, but financed privately. Naturally, companies won't spurn any handouts that might be forthcoming.

But private enterprise is powering forward with conviction, from Aberdeen to Australia, essentially unsubsidised and without government direction: rapidly advancing the technologies involved, slashing the hardware costs and planning large-scale experiments that could pave the way for a potential future roll-out.

A hydrogen bubble? There's no saying whether this will bear fruit, particularly at the residential level: to repeat, the problems are many and great. But don't lightly dismiss anything that good engineers in large, capable firms, working hard with proven and relatively conventional technologies, consider feasible. And, thus far, it's mostly their own money!

"Old sparky" has clearly missed the point.  I sent off a letter to the editor which I will reproduce here in case it never gets printed

Sir,

Old Sparky writes [Eyes 1549] that "the total consumption of gas used for heating and cooking exceeds the consumption of electricity for all uses" before going on to add to the existing hype for hydrogen as an alternative to heat pumps.  This may be true, but it is a meaningless comparison as an electric heat pump consumes much less electrical energy than the heat energy it moves.  And since hydrogen manufacture is also wasteful, a reasonable estimate is that our homes would require 6 times more wind farms if heated by hydrogen boilers than if they were heated by heat pumps.

Sparky writes that "The obvious suspects (National Grid, the nuclear industry)" are promoting replacing gas with electricity.  But who is pushing hydrogen, and why? Follow the money and you find 58M euro spent by fossil fuel companies lobbying Brussels for the hydrogen economy.  The reason: 99% of hydrogen does not come from electrolysis of water, but from using natural gas as a feedstock - a process that generates more CO2 per usable kilowatt hour than just burning the stuff.

FOOTNOTES

(*) Hydrogen fuel cell cars are also pretty inefficient - about half as efficient as Electric Vehicles.  That's unsurprising because you convert the electricity to hydrogen and back again to electricity! Both Elon Musk and Herbert Diess (the head of VW) have pointed this out but it hasn't stopped the German government pushing this bleeding edge technology hard!