Hydrogen heating – a silver bullet or hot air?

14 June 2023 3842 Views

At present, the space heating of homes accounts for roughly 14% of the UK’s annual emissions. If we are to meet our 2050 net zero target, home heating must be decarbonised. With 83% of homes in the UK warmed by fossil fuel boilers, it is clear something will have to change. Although heat pumps are the government’s current preferred option for decarbonising home heating, hydrogen has become a hot topic in the media recently.

For some, hydrogen heating offers a silver bullet solution that can reduce household emissions while utilising our existing gas grid and home heating systems. These arguments mainly come from the UK’s gas industry, who have united under the guise of ‘Hello Hydrogen’, a campaign aspiring to raise awareness of the role that hydrogen can play in decarbonising homes. The campaign has even enlisted Rachel Riley of Countdown fame as their latest campaign ambassador.

But is the hype around hydrogen heating all just hot air? Well, some seem to think so, viewing hydrogen as a more-expensive, less-green distraction from an already proven low-carbon heating solution – heat pumps. The question is, who is right?

To assess the suitability of hydrogen heating let’s look at the facts, starting with how our hydrogen demand will be met. Unlike the gas we use now, naturally occurring hydrogen is hard to locate and extract. For this reason, we will have to artificially produce most of the hydrogen we need. Possible though it is to produce low-carbon hydrogen, known as either ‘blue’ or ‘green’ hydrogen, to do so at scale is expensive, hence low-carbon hydrogen only accounts for a fraction of the global share.

Once produced, the theory is that we can use our existing gas grid to deliver hydrogen or a hydrogen gas blend to our homes. However, in practice it is not this simple. The main complications arise when the gas supply surpasses 20% hydrogen, as any greater hydrogen content than this would damage the grid’s pipes, valves, and pumps. The prospect of changing all of these for hydrogen supportive materials will evidently be costly, complicated, and time consuming.

For hydrogen to then heat our homes, it must be burned in a boiler, like those already used for natural gas. Hydrogen boilers come in two types: ‘hydrogen-blend ready’ and ‘hydrogen-ready’. ‘Hydrogen-blend ready’ boilers are already on the market and in many homes; they can burn both natural gas and a gas blend of up to 20% hydrogen. ‘Hydrogen-ready’ boilers are still in the design stage but will be able to burn 100% hydrogen gas; manufacturers estimate they will become available anywhere between 2023 and 2028. Both boiler types look very similar to regular natural gas boilers and will require a couple of parts to be changed before they can run on hydrogen.

When it comes to the government’s stance the jury is still out. While trials and research are still ongoing, the government has said it will refrain from making a ‘strategic decision’ on the role of hydrogen in heating until 2026. We can expect some inclination of the future role for hydrogen later this year with the Energy Bill – which is working its way through parliament – set to outline commercial arrangements for hydrogen production and further trials.

At present it does not seem to make environmental or economic sense to use hydrogen instead of heat pumps to decarbonise heating. However, this does not mean that hydrogen will have no part in home heating. It is highly likely that over the coming years some hydrogen will be introduced into the UK’s gas supply to help lower its carbon intensity.

Although it is always worth exploring and researching emerging technologies, the noise surrounding hydrogen risks drawing attention away from established and effective technology. Until we know the government’s 2026 decision on hydrogen heating, it is important to continue pursuing space heating decarbonisation with the proven solution – heat pumps.

You can read more about the future of home heating on the Sava blog.

This article was written by Johnnie Leather, Public Policy Researcher at Sava. For 40 years, Sava has been ‘Making Buildings Better’ by providing education, technology and professional services to help look after the UK’s 29 million homes. To find out more about Sava’s work in the residential sector, visit www.sava.co.uk.