​Hydrogen for Domestic Heating: Progress and Considerations

Hydrogen for Domestic Heating: Progress and Considerations

With the UK's firm commitment to achieve Net Zero by 2050 and domestic heating and hot water accounting for around 17% of the nation's carbon emissions, it is vital that we find a way to decarbonise UK homes.

The UK's electricity grid is steadily becoming greener, largely owing to the significant expansion of offshore wind energy. Electrification emerges as a pivotal strategy for decarbonising residential heating.

Heat pumps stand as the primary low-carbon heating solution endorsed by the UK Government, with ambitious targets set for 600,000 installations annually by 2028. Other low carbon electric technologies and heat networks with Heat Interface Units will also play a part in achieving Net Zero by 2050. It’s clear we are going to see a real diversification of technology used to heat our homes.

At the moment over 80% of UK homes are connected to the gas grid and rely on gas boilers for their heating and hot water needs, this raises a crucial question: Can we provide a decarbonised gas and can hydrogen provide the answer?

Hydrogen seems like a promising alternative due to its clean-burning properties, producing water as a byproduct instead of carbon dioxide, although it does generate some byproducts like NOx, similar to natural gas combustion. However, the feasibility of hydrogen hinges on several aspects that require scrutiny.

Manufacture

Unlike natural gas hydrogen needs to be manufactured, which takes energy that, in turn, needs to be low carbon. Hydrogen is often categorised by colour; green hydrogen is made through the electrolysis of water, with the electricity used from renewable sources such as wind power. Blue hydrogen is made through the steam reformation of methane; here carbon dioxide is a byproduct, and it has to be captured and either stored or used through a process called CCUS (carbon capture, usage and storage). If the carbon is not captured and it is released then the hydrogen is termed grey hydrogen and generates carbon emissions, which defeats the purpose.

Cost

The cost of hydrogen remains uncertain, and early on, it may require financial support to be cost-effective.

Prioritisation

Hydrogen is really useful for decarbonisation and has the potential to be used in many industries. There are some big decisions to be made by Government about where hydrogen will be used; is it best prioritising heavy industry, freight, ceramics, steel, glass or home heating?

Technical Feasibility

We get asked regularly whether we can run a boiler on hydrogen, and the answer is yes, we have R&D teams working on boilers that can operate safely and effectively on hydrogen and we have had boilers running on hydrogen. Gas networks are also confident about their ability to convert the gas grid for hydrogen use. The UK Government has not dismissed the possibility of using hydrogen for domestic heating, given its potential to offer a familiar solution to homeowners.

However, it's essential to acknowledge that hydrogen's adoption may not be as widespread as natural gas, and its availability could be limited.

20% blend

You may hear about the potential for a proportion of hydrogen to be added into the natural gas grid at a level of up to 20%. This has the potential to partially decarbonise the gas grid if it goes ahead. Domestic boilers are already designed to run on up to a 20% hydrogen blend. Testing of domestic boilers to European standards includes testing with G222, a limit gas of up to 23% hydrogen. Successful trials, like Hydeploy at Keele University and in homes in Northeast England, which Ideal Heating participated in, have demonstrated positive results with up to a 20% hydrogen blend.

Hydrogen ready boilers

So what is a “hydrogen ready boiler”? A hydrogen ready boiler is defined as a boiler that leaves the factory and is installed on natural gas. When instructed to run on hydrogen it can then be converted using a conversion kit. There is currently a potential that UK Government will mandate that all boilers are “hydrogen ready” in the future so they can be converted if needed. At present we are not aware of any hydrogen ready boilers on the UK market.

What’s next?

Ongoing and planned trials related to hydrogen and domestic heating are in progress. Critical decisions by the UK government include the potential decision to blend up to 20% hydrogen into the gas network by the end of 2023 and, by 2026, whether hydrogen will be adopted for domestic heating. If and when such a decision is made, it will take several more years before hydrogen becomes a widespread heating solution.

In the meantime, focus can be directed toward alternative decarbonisation methods, including heat pumps, electric products, and heat networks, while ongoing research and development efforts continue to refine hydrogen boilers.

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