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Hydrogen Heating: 'World-First' Trial Begins in Wales

Pembrokeshire County Council's hydrogen heating trial begins
(Image credit: Pembrokeshire County Council)

A hydrogen heating trial has begun in Wales which will test the 'world's first' hydrogen hybrid heating system. 

The system combines a Worcester Bosch boiler that runs on hydrogen and an air source heat pump, which will be installed at a commercial building at the Port of Milford Haven and managed using a smart control system developed by Passiv UK.

The system can automatically switch between using the heat pump or boiler, depending on energy supply factors linked to cost and availability. 

And every two minutes it will access the availability of renewable electricity in the grid to determine how to best heat the building. When there is not enough renewable electricity, it requests the boiler to power the building. 

Dr Stephen Wyatt, from the Offshore Renewable Energy (ORE) Catapult, one of the lead partners in the project, said: “This world first is both an important milestone for the project, but crucially provides a concrete example of how we can achieve the energy transition using technologies which are readily deployable in our existing building stock."

Why is Hydrogen Heating Being Developed?

Hydrogen could have a key role to play in heating existing homes while lowering carbon emissions from natural gas boilers.

Currently around 85% of UK homes are heated with polluting natural gas, and hydrogen technology is considered by experts to have a key role in helping the UK reach net zero by 2050. This is because the main by-product of burning hydrogen gas is water, which represents a way of greening up the gas grid.

While renewable tech such as air source heat pumps and ground source heat pumps, which run off electricity, will be vital in heating our homes this technology might not be suitable for all homes. 

Blending hydrogen into the gas grid could also help to cut emissions from homeowners' gas stoves and from gas power plants that supply electricity to homes and businesses.

What is a Hydrogen Boiler?

Hydrogen boilers have been developed by manufacturers such as Baxi Heating, Worcester Bosch and Viessmann to run on 100% hydrogen as well as natural gas.

This means that transferring to hydrogen gas in the future will be easy for those with a hydrogen-ready boiler because it can convert to hydrogen without the need for an entirely new heating system.

While 100% boilers are not yet available (more on this below), hydrogen-ready boilers are available which can run with a hydrogen mix of up to 20%. These boilers will enable a smooth transition to hydrogen when hydrogen is introduced to the UK gas grid, without changes to cookers or boilers. 

In February, the Heating and Hotwater Industry Council revealed a new labelling system for hydrogen appliances that has been agreed by its appliance manufacturers. The new labels will display three distinct categories of hydrogen appliances:

  • 'Hydrogen Blend' compatible - capable of running on a blend of up to 20% hydrogen in the gas network.
  • 'Hydrogen-Ready' appliances - capable of running on a 20% blend but with the capability of being converted to run on a 100% hydrogen gas network
  • '100% Hydrogen' boiler - capable of running on hydrogen without the need for conversion.

Hydrogen heating is being tested in several UK trials

Baxi Heating's boiler is being tested in several UK hydrogen trials. (Image credit: Baxi)

Homes Might be Heated by Hydrogen in 2023

The Energy Networks Association (ENA), the industry body representing energy network operators in the UK, said last month that it is preparing capability to introduce 20% hydrogen into the regular gas grid from 2023.

If this 20% capacity is achieved, it would represent an equivalent reduction of taking 2.5 million cars off roads, in terms of reducing carbon emissions.

The ENA has set out two possible rollout models for the government to select, depending on the volume of hydrogen production that will be available for blending in 2023. These models are: 

  • The 'strategic approach’ - connection locations would be based on the most suitable parts of the gas network
  • The 'free market approach’ - hydrogen capacity would be available to the free market on a ‘first come, first served’ basis

The ENA is targeting for homes to benefit from hydrogen as a replacement for up to a fifth of the natural gas currently used, from the winter of 2023.

It also hopes this move will signal to government that networks are ready for ramped up hydrogen production, and called on the government to double its domestic hydrogen production target from 5GW to 10GW in 2030.

How Will Hydrogen Heating Work in Our Homes?

The future of hydrogen heating in homes will most likely be a combination of a heat pump and a hydrogen boiler, according to Remeha, part of BDR Thermea Group in the Netherlands.

The Netherlands are frontrunners in the development of hydrogen heating, which has a huge, comprehensive natural gas distribution network and is in the midst of transitioning from natural gas to zero carbon: either through electricity, hydrogen or biogas. 

Remeha says that the complexities of each of the two low-carbon heating options means a combination of the two - such as the system currently being trialled in Wales - would be the likeliest way to effectively heat our homes. 

Rick Bruins, business development manager at Remeha told Homebuilding & Renovating that a small heat pump would be effective for tackling outside temperatures up to 0ºC, then when it starts to freeze, the boiler would begin to heat up the home. 

“Installing a heat pump with enough power to heat a home which is -10ºC is very expensive, but hydrogen is expensive too, so the combination of the two would make for a cost-effective solution,” said Bruins.

Based on estimates from the Dutch government and local energy suppliers, hydrogen will be heating homes in the Netherlands within 15 years.

changing existing gas boilers for hydrogen heating could be expensive

Many homeowners could eventually change their natural gas boilers for hydrogen boilers  (Image credit: Getty Images)

Is Hydrogen Heating Safe?

Heating homes with hydrogen was shown to be feasible and safe in September 2021, following the results of the first HyDeploy pilot trial at Keele University, where 20% of hydrogen was injected and blended into Keele University's existing private gas network, which supplies 30 faculty buildings and 100 domestic properties.

And while a study in August claimed hydrogen boilers could cause four times more explosions than natural gas boilers, it also revealed that this could be fixed by installing two excess flow valves to easily regulate how hydrogen flows through the pipes.

Martyn Bridges from Worcester Bosch said of the study: “The headline should have been that these boilers will save lives because there is no carbon monoxide created from hydrogen, which is by far the biggest hazard with burning gas. We are very confident that hydrogen is safer than natural gas.” 

2026 Delay for Hydrogen Decision

In 2021 the government confirmed in its Heat and Buildings Strategy that while 100% hydrogen heating is being trialled nationwide, it will not make a firm decision on what role hydrogen will play in heating the UK’s homes until 2026.

Despite this announcement, the government in recent years has stated its committed to hydrogen heating. 

The government's 10-point plan published in November 2020 pledged to develop the first town powered entirely by hydrogen by 2030, with milestone targets along the way: starting with a hydrogen neighbourhood in 2023, moving to a hydrogen village by 2025. 

The Humber could reportedly be one of the first towns to trial hydrogen in its pipes through the conversion of the local grid and the replacement of boilers, meters and hobs.   

The government has also invested £25m into the Hy4Heat programme, a pilot scheme in Scotland to heat 300 homes with 100% hydrogen via the existing gas grid due to take place in 2023.

And while only a handful of pages in the Hydrogen Strategy in August were dedicated to heating in the home, it laid out the groundwork for ensuring up to 35% of the UK’s energy consumption comes from hydrogen by 2035.

The Strategy also pledged that hydrogen will power up to three million homes by 2030, and that the government will look to enable or require new gas boilers to be easily convertible to hydrogen by 2026. 

Hydrogen heating trials are taking place across the UK

Worcester Bosch's hydrogen boiler prototype. (Image credit: Worcester Bosch)

How Expensive is Hydrogen Heating?

One of the main criticisms of hydrogen heating is that it can be costly to produce, which could limit its availability. This is because it relies on either using renewable energy to split water into hydrogen and oxygen (the process used to make 'green hydrogen'), or using carbon capture technology to prevent emissions being released by splitting fossil fuel gas into 'blue hydrogen'.

Environmentalists including climate think tank E3G, WWF, and Greenpeace have previously urged the government to ignore what they call “hype” over the use of hydrogen to provide heat, citing the expensive processes to create green hydrogen and expressing doubts over the environmentally-friendly credentials of carbon capture technology used to create blue hydrogen.

However, in July, the boiler industry’s big four manufacturers confirmed that a hydrogen-ready boiler will cost no more than its natural gas equivalent. Baxi, Worcester Bosch, Vaillant and Ideal confirmed that a new price-promise will be introduced which could save homeowners £2.3 billion. 

Boiler Guide estimates that pricing would be similar to natural gas boilers - somewhere between £400 to £3,000 before factoring in the installation.

Which Other Trials are Ongoing?

Low Thornley, Gateshead

The UK's first homes to be fuelled entirely with hydrogen heating officially opened for public demonstration in July 2021. The two semi-detached homes based at Northern Gas Networks' innovation site in Low Thornley, Gateshead are powered entirely by hydrogen boilers — developed by Baxi Heating and Worcester Bosch.

All of the appliances including hobs, cookers and fires are hydrogen-powered, and these will be rotated so different manufacturers can showcase their innovations and seek consumer feedback. 


In November 2020, Baxi and Worcester Bosch boilers were installed into the first UK homes to demonstrate the technology’s efficiency.

The innovative prototypes are being trialed at The ‘HyStreet’ test site in Northumberland, which consists of specially built demonstration houses. More than 200 tests will now be completed to research and prove the safety and efficacy of converting homes and gas networks to hydrogen.

The current trials in Northumberland will demonstrate how existing gas networks can be repurposed to safely carry 100% hydrogen.

This 100% BDR Thermea Hydrogen Boiler is currently being tested in hydrogen heating trials

(Image credit: BDR Thermea Group)

Fife, Scotland

Fas network operator SGN submitted plans in 2021 for H100, the world’s first domestic hydrogen heating grid. The first homes in the world to use green hydrogen through a local gas grid , in Fife, Scotland, are expected to receive the hydrogen in early 2023. 

Keele University

In 2020, in the first HyDeploy pilot trial, 20% of hydrogen was injected and blended into Keele University's existing private gas network, which supplies 30 faculty buildings and 100 domestic properties.

And in September, the published results revealed that the hydrogen blend had no adverse effects for users, and had the potential to reduce carbon emissions.

A total of 42,000 cubic metres of hydrogen were blended into the gas network, which reportedly led to 27 tonnes of carbon dioxide being preventing from entering the atmosphere.


Three purpose-built houses at the RAF Spadeadam base in Cumbria are being used to test out 100% hydrogen homes.


The H21 is a series of a test projects that aim to prove the gas grid can be converted to hydrogen, which are being conducted on a wild hillside at a Royal Air Force base. 

Tim Harwood, who is running the H21 pilot project near Carlisle, says the gas grid could be ready to switch to hydrogen within two years, but has called for greater hydrogen capacity to be made available by the government. 

Winlaton, Gateshead

In a separate HyDeploy trial in Gateshead, 670 homes will be some of the first in the UK to trial natural gas blended with hydrogen. The project began in early 2021 and is expected to end later this year. 


A £4.8m hydrogen hub to be set up in Wales to pilot the creation of hydrogen from renewable energy was announced in the Spring Budget. 

Jack has worked in journalism for 11 years and is the News Editor for Homebuilding & Renovating, a role he has had since 2019. He strives to break the most relevant and beneficial stories for self builders, extenders and renovators, including the latest news on the construction materials shortage and hydrogen heating. In 2021 he appeared on BBC's The World at One to discuss the government's planning reforms. 

He enjoys testing new tools and gadgets, and having bought his first home in 2013, he has renovated every room and recently finished a garden renovation.