What's in this article?
The UK government is serious about meeting its carbon neutral goals and since natural gas is a major contributor to carbon emissions, low carbon alternatives such as hydrogen are likely going to be its replacement in the coming years.
Note: It’s not yet possible to purchase a hydrogen-ready boiler, but industry leaders such as Worcester Bosch, Viessmann and Baxi continue to make significant progress with their prototypes and testing.
March 2021 Updates: The Energy Minister announced the first homes with hydrogen boilers in the UK are planned for April 2021 and will be built in Gateshead, London.
National Grid Hydrogen Project: From next year, Fife, Scotland will become the first location in the UK where hydrogen appliances will be trialled in over 300 homes and fed with hydrogen gas directly from the grid.
Why is it important to have an alternative to gas boilers?
One of the major causes of global warming is the production of greenhouse gases through the burning of fossil fuels, like natural gas.
These gases cannot escape the atmosphere and instead remain trapped, causing the earth’s temperature to rise.
In response to this global climate emergency, in 2016, at the Accord on Climate Change in Paris, the UK government, together with the world’s largest economies agreed to tackle global warming by becoming carbon neutral by 2050.
As a result, traditional heating methods, which currently account for one-third of UK carbon emissions, are at the heart of the government's low carbon agenda and change is inevitable.
Low carbon heating methods are an essential ingredient to achieving the targets; this includes technologies such as heat pumps, solar, biomass and the adoption of hydrogen boilers.
Residential boilers have already been the target of substantial legislation, including a ban on non-condensing boilers, rendering all new boilers at least 90% efficient, as well as a complete ban on gas boilers in all new build properties from 2025.
However, the reality is that most UK homes use gas boilers for heating and the expense and viability of replacing all of them with solar and heat pumps is not considered achievable by many observers.
Due to this, hydrogen-ready boilers are seen as the most viable solution, since they can make use of the existing infrastructure, engineers and their price point will likely remain competitive.
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So, why hydrogen boilers and not solar or heat pumps?
There remain several barriers to the adoption of low carbon heat and a recent report by the Environmental Audit Committee (EAC) found that it will take over 700 years for the UK to make the transition at its current speed.
Additionally, the Committee on Climate Change (CCC) has estimated that it would cost an average of £26,000 to switch each UK home to a low-carbon heating system.
One potential solution to these barriers is hydrogen fuel, which takes advantage of the current gas infrastructure, which is connected to 8 in 10 homes. Therefore, many industry commentators assert that it’s much more practical to change the fuel instead of the heating system in every home.
When hydrogen is burned it produces only vapour and no carbon dioxide, so the feasibility of delivering it into homes via the gas network are currently under review by the EAC and CCC.
What is a hydrogen boiler?
Hydrogen boilers look almost identical to the present day gas boiler and are also installed in pretty much the same way. Like gas boilers, they would be connected to the gas mains and hydrogen or natural gas fed to them from there.
The internal components would be very similar to present day gas boilers too. Minor differences include different components such as a hydrogen-ready flame detector and burner.
It’s thought that when and if the gas network transitions to using hydrogen, Gas Safe Engineers will be provided with new training specifically covering hydrogen gas and the installation of hydrogen boilers.
Can you buy a hydrogen boiler today?
As of early 2021, it’s not yet possible to purchase a hydrogen-ready boiler, nor would it make much sense, since there is not yet any reliable supply of hydrogen gas.
Both Worcester Bosch and Viessmann have been working on their hydrogen-ready prototypes for several years now and have made significant progress, with both companies trialling them in certain “test areas” within the UK.
It’s thought that hydrogen-ready boilers will be rolled out in the coming years, likely from 2025 and beyond, to coincide with the proposed gas boiler ban in new build properties.
The major advantage of a hydrogen-ready boiler is that it can continue to use natural gas until hydrogen gas is available. This will allow the whole country to transition to the low carbon alternative in a strategic way and with almost no disruption to home heating.
Advantages (and disadvantages) of hydrogen boilers
Market leading boiler manufacturers Viessmann and Worcester Bosch have been developing their hydrogen ready boilers and continue to update the industry on progress.
This new technology is able to utilise both natural gas and hydrogen, making them the ideal transition appliance as they can be used before and after the new fuel is supplied.
So, why does hydrogen receive so much positive attention?
Emissions contain zero carbon ✅Fossil fuels such as coal, oil and gas are all high-carbon fuels that emit carbon dioxide when burned. This is a leading cause of global warming. Hydrogen on the other hand, only produces water, with no carbon dioxide.
Existing Gas Infrastructure can be used ✅One of the biggest benefits of hydrogen is that it only means changing to fuel supply, so it is much easier and quicker to roll out nationwide. It also avoids the costs and learning curve of households adopting completely new heating systems.
Hydrogen is more efficient than Gas ✅There is equal energy in 1kg of hydrogen as there is in 2.8kg of gas that means you can heat homes just as well but use less fuel in the process.
Disadvantages of hydrogen boilers
Unfortunately there are some concerns about the feasibility of hydrogen heating, but this is currently being reviewed by the EAC and CCC.
Hydrogen is not cheap to produce ❌The energy company Centrica believes that hydrogen is certainly part of the mix, but believes the technology is at least 10 years away from producing it cleanly and costs are unknown.
Currently there are two leading methods of hydrogen production: electrolysis or Steam Methane Reforming (SMR).
Electrolysis works by splitting water molecules into two separate hydrogen molecules with the use of a high voltage current. When the electricity used is generated using renewable energy, and then this is the most eco-friendly method of producing hydrogen.
The second leading method is Steam Methane Reforming which is the method of reacting steam with methane. A by-product of producing hydrogen this way is a carbon by-product. Although it isn’t all negative, since the carbon produced can be captured before it’s released into the atmosphere.
Right now, both hydrogen production methods are expensive and so are not viable for the mass market where megatons of hydrogen will be required to provide nationwide supply.
Hydrogen is flammable ❌Gas is flammable, but hydrogen is arguably even more flammable due to its energy store, however, it also doesn’t have a smell, so detectors are an essential part of their use to ensure safety is maintained.
Storage isn’t Easy ❌Hydrogen isn’t as heavy as natural gas and so it is much more difficult to store and transport. In order to achieve adequate conditions, it needs to be turned into a liquid and stored at a low temperature.
When will hydrogen-ready boilers be available in the UK?
As mentioned, major industry leaders Worcester Bosch, Viessmann and Baxi have developed prototype hydrogen-ready boilers.
However, hydrogen fuel production is another area that needs a solution, which is why the UK government is collaborating with industry and researchers. Current projects include the following:
HyDeploy is a research project being carried out at Keele University, Staffordshire and is testing the viability of using a natural gas and hydrogen mixture on the current network. Specifically, they are testing a 20:80 blend which would mean no substantial changes would need to be made to boilers or the installation process.
A 20:80 blend is planned to be rolled out from 2025. AS of 2020, the project is under review by the Health and Safety Executive (HSE).
Hy4Heat is a project researching the viability of a complete hydrogen network.
In 2020, the project released extremely promising results. A key part of the project was looking at how appliances can be used in a safe manner, as with natural gas, safety is a major concern. In addition, there are slight differences between hydrogen and natural gas, such as smell and visibility and so ensuring gas installers are well trained is also an essential part of the research.
Hydrogen Supply Programme
There are numerous global projects in operation that aim to find an efficient way to produce hydrogen and supply it to residences. In 2020, the UK government made a 20 million pounds pledge to the Hydrogen Supply Programme, which helped to fund the HeDeploy project at Keele University.
The National Grid Hydrogen Project
The National Grid in partnership with organisations such as OFGEM, SGN and the Scottish Government are trialling hydrogen use on the grid to help prepare for the UK's low carbon future.
The project will involve over 300 homes in Fife, Scotland being fitted with hydrogen boilers, cookers and appliances and fed with hydrogen gas at no extra cost by the end of 2022. It is anticipated that eventually 1,000 homes could be included in the trial, which is set to last around 4 years.
You can read more about the National Grid's ambitious plan's here.
How much would hydrogen boilers cost?
As no commercial available hydrogen boiler exists, the current price is unknown.
Yet, most would agree that industry is aiming to release a hydrogen boiler that will be as attainable as current gas boilers.
At present a standalone combi boiler or system boiler can cost between £600 - £900 for a budget model, £900 - £1,200 for a mid-range model and £1,000 - £2,000 for a premium model depending on the size of the boiler. A regular or heat-only boiler can cost anywhere between £500 - £2,000 depending on the size and quality.
However, it’s important to consider other factors too, such as the brand of boiler you choose, your current type of boiler and whether you want any extras e.g. filters, or whether you want to move your boiler to a different location.