The debate over decarbonisation of heat is marked by polarised views from the passionate advocates of electrification and green gas - each with a statistic at the ready to prove their case. As part of Utility Week’s Countdown to COP series, David Blackman unpicks the arguments and examines the key question for policymakers - what role hydrogen will have in warming the homes of the future?

It has become a bitter dividing line, which inflames passions more intensely than any other topic in today’s energy sector.

For those who don’t spend every waking hour on Twitter, we’re talking of course about the great hydrogen versus heat pump debate.

This debate is getting so much air-time currently because advocates of the two technologies are seeking to shape two key strategy documents, covering heat and buildings and the other hydrogen, both of which are on the verge of publication.

David Watson, head of energy transition of Cadent, urged the two camps to dial down the rhetoric at Utility Week’s Future of Heat conference.

In his keynote comments, he said: “We definitely need to end the format wars. The constant argument about hydrogen v heat pumps is unhelpful and is getting in the way of delivering both.”

However, the authors of a letter sent earlier this month by green groups to energy secretary Kwasi Kwarteng clearly hadn’t listened to this dovish message.

The correspondence, which was co-ordinated by consultancy E3G and backed by the likes of Greenpeace, describes proposals to make the gas network hydrogen-ready as a “Trojan horse” for continued use of fossil fuels for home heating.

In particular, the letter urges the government not to move ahead with blending hydrogen into the gas in the national network or mandating the introduction of hydrogen-ready boilers.

“With the best will in the world, we may not want the debate to be about molecules v electrons but it is,” says Mike Foster, chief executive of the Energy and Utilities Alliance.

The bad feeling between the two camps partly stems from suspicions that many of the companies behind the push for hydrogen are the same fossil fuel companies that have helped to pump so much greenhouse gas into the atmosphere over the last century.

“From the hydrogen side there are enormous, vested interests,” says Bean Beanland, president of the Ground Source Heat Pump Association.

“From the electric side, the feeling is that they have had it their own way so it’s time to move over.

“The difficulty for the electric side is that the fossil fuel hydrogen side is very mature and incredibly well funded.”

For the gas industry the heart of the issue is that a push to electrification poses a potentially existential threat to its existence and the infrastructure it has taken decades to develop, he says: “The risk of stranded assets is huge so there is a lot to play for and they feel they have to fight tooth and nail.”

Doug Parr, head of policy at Greenpeace UK agrees: “The gas industry knows it’s in a lot of trouble. It has nowhere to go under a genuinely zero-carbon energy system and they want to preserve their existing assets and business models.”

Nothing to see here

Foster rejects the notion that the push to boost hydrogen production is just a plot by fossil fuel companies to prop up under-threat business models.

The renewable energy and seawater, which are the resources required to make green hydrogen through the electrolysis process, can be found across the planet, he says: “This isn’t lobbying by the gas networks in the UK: it’s a global solution to a global problem.”

And it will cost too much to increase their energy efficiency to the point where heat pumps can be effective, Foster says: “If you genuinely believe you need a gas network because some homes are not suitable, by definition you must pump hydrogen into the gas network.”

Clare Jackson, co-lead of the Hydrogen Taskforce Secretariat, argues that both technologies will be required for home heating.

“The debate seems to be dominated by people with more polarised views, but if you talk to the vast majority there is a recognition that we need both.

“Hydrogen is not a silver bullet but not all homes are suitable for heat pumps. We know that there is a need for both of these technologies.”

While acknowledging that heat pumps are a more efficient way of providing heating, hydrogen has “huge benefits” as an inter-seasonal storage mechanism, she says: “A mix of heat pumps with some hydrogen is way to go, like the Mastercard advert, loads of homes are suitable for heat pumps: for everything else there is hydrogen.”

“We all think heat pumps should be deployed as fast as humanly possible. Doing hydrogen trials and pilots is not an excuse to take the foot off the pedal, we need both. Let’s not close any of these options off.”

Foster adds that the injection of hydrogen into the gas network will help to spread the costs of decarbonising, which otherwise will be felt more sharply by some households than others.

“Over 40 years, it becomes a manageable sum. If you are decarbonising individual homes off the gas grid, you don’t have that socialised option.”

Parr dismisses these arguments, although he concedes they are “seductive” for policymakers because they keep in operation what would otherwise become stranded assets.

“The beguiling thing is that hydrogen holds out the prospect of solving political and institutional difficulties by switching fuels. It is beguiling but it kicks the problem down the line because you will start to have to move to heat pumps and insulation in due course so you have just created massive stranded assets and put off resolving the problem.”

How green is hydrogen?

The problem with hydrogen-ready boilers and injecting the gas into the grid is that it keeps this polluting form of heating.

Green hydrogen, the low-carbon production process that uses electrolysis to release hydrogen from water, is still very expensive to produce. This means that for years to come, the hydrogen that will be injected into the network will predominantly be the so called blue type, which is made from breaking down natural gas, and creates emissions.

The only way to minimise emissions from the blue hydrogen production process is through “enormous amounts” of carbon capture and storage that Parr doesn’t believe will be delivered.

He says: “The concern about hydrogen for heating is not driven by an anti-capitalist desire for oil companies to get their come uppance: it’s driven by the fact that the maths don’t stack up.

“We can’t go down this route big time, now will be very, very clear that can’t go down the hydrogen heating route because you can’t deliver the emissions reductions necessary.”

He argues that the supply of “green” hydrogen, or eco-hydrogen, will always be limited and be too valuable a resource  to be used for home heating.

Instead, he believes it should be reserved for areas like industry and long-term power storage where fewer decarbonisation alternatives exist.

“You’re going to need hydrogen and quite a lot of it. You can argue will be other technologies that might do the job but in terms of versatility hydrogen has a lot to offer.”

“It seems that home heating is not the place you would not want to put it when we know alternatives exist and can and should be rolled out,” Parr says, citing heat pumps and district heating as two well-established alternatives.

Even once the government’s planned expansion of offshore wind power has taken place, there may be more resource efficient ways of using any spare electricity generated by this intermittent source of power, such as exporting it via interconnectors to the Continent.

However, if the whole northern Europe embraces wind power as enthusiastically as the UK, there could be spare electricity that could be best harnessed for hydrogen production, he says: “There could be periods when we have more than enough (electricity) for ourselves and if you can’t shift it offshore, not curtailing and using it for hydrogen would be a good use.

“We are going to be electrifying both transport and heat so using it for grid balancing would be a good thing,” Parr says, adding that it could also help to take the edge of peaks of demand by providing back up generating capacity for electric district heating systems.

The idea that insufficient hydrogen will be available is wrong, says Foster: “The same arguments were made about wind power. As more capacity comes on stream, costs will plunge: exactly the same will happen with green hydrogen.”

So far, the government has said that it wants 600,000 heat pump installations by 2028 while backing pilot projects for hydrogen home heating, which is due to culminate in a town-wide trial.

But the fractious debates could understandably leave policymakers confused, says Beanland: “They don’t know which side to believe.”

And the arguments will continue unless the heat and buildings strategy, which was due to be published nearly a year ago originally, provides some clearer pointers about the future direction of home heating.

As Foster puts it: “There is a vacuum where government policy should be.”

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