Hydrogen – The Key to Clean Energy

With the UK net zero target set at 2050 and 31% of household emissions currently coming from central heating, the industry needs to look at the bigger picture of how to heat UK properties.

Hydrogen is the key to the green industrial revolution for transport but most importantly, heating. Here at Vaillant we pride ourselves in being at the forefront of technology which is why we are already developing hydrogen boilers and are on our way to emission free heating solutions.

What is Hydrogen and Where Does It Come From?

Three Ways to Produce Hydrogen

Hydrogen in Buildings

How Heating with Hydrogen Works

Hydrogen and Today's Products

What Are We Doing to Support You and Your Business

Sign Up to Training

Why Hydrogen?

What is Hydrogen and Where Does It Come From?

Hydrogen can be obtained from a wide variety of substances, but above all, from water which the earth has an abundance making it a secure energy for the future. Hydrogen has another decisive advantage: It is a climate-friendly and, when producing green hydrogen, it is even a climate-neutral energy carrier.


The only by-products of green hydrogen are oxygen and water.


Hydrogen is capable of lifting the space shuttle and will keep planes in the air for hours, so it is more than capable of heating our homes.

Unlimited availability

Hydrogen can be obtained from different substances, especially water. And we have an unlimited source of water on earth.


It can be a fuel or a coolant, generate electricity and heat. And it has even more potential in the future.

Along with Oxygen, hydrogen is the main component of water. It is a very light gas with the chemical formula H2 and has a huge potential to make the transition to a carbon-neutral energy supply.

Hydrogen does not naturally occur in its pure form. It needs to be produced. There are different ways of doing this, the most common terms to describe the way of production are green, blue and grey production - depending of the amount of CO2 emissions during the production process.

Green Hydrogen is considered the fuel of the future, for a simple reason: a zero carbon emission process. Green Hydrogen is efficient and 100% sustainable. Experts calculated that a change from grey to green hydrogen will already save 830 million tonnes of CO2 that are emitted annually. In the UK, green hydrogen is the aim but to begin with, there will be a mix of blue and green hydrogen.

To learn more about hydrogen's role of reducing future carbon emissions, sign up to our 'Hydrogen: The Role of Green Gas in the Decarbonisation of Heat' CPD.

Three Ways to Produce Hydrogen

Hydrogen molecules (H2) are extremely rare on earth in their isolated form but there are numerous methods to extract hydrogen from water (H2O) or methane (CH4).

Green: Carbon-neutral

(1) By passing an electric current through water, we can break it down into oxygen and hydrogen, this process is called Electrolysis. If we only use sustainable generated electricity, such as wind or solar PV, the process does not generate any carbon emissions. (2) The hydrogen can then be stored in tanks or even underground caverns and transported via pipelines, tankers or trucks. (3) It can then be used wherever gas or other energy sources have been used so far.

Blue: CO2 is stored

Blue hydrogen is produced from natural gas. The CO2 that is produced is not released into the atmosphere, but up to 90% of the CO2 can be stored in tanks or underground caverns preventing emissions. Lifecycle carbon emission savings of up to 85% are possible with blue hydrogen when compared to natural gas boilers. (Source: The CCC)

Grey: CO2 is released into the atmosphere

Like blue hydrogen, grey hydrogen is produced from natural gas. However, the CO2 is not stored underground in this process, but gets released into the atmosphere and causes emissions. The ratio of hydrogen to CO2 is 1 to 10, meaning that 10 tonnes of CO2 are emitted for only one tonne of hydrogen.

Hydrogen in Buildings

Hydrogen can be burnt in boilers for domestic or light commercial use. Today, Vaillant already offers boilers that can burn a mixture of hydrogen and natural gas. In the UK, the journey to fully decarbonised heating systems is a long term vision, but in an effort to lower carbon emissions on the way to a full hydrogen infrastructure, networks are currently being tested to supply a mixture of up to 20% hydrogen with natural gas. But, to have a fully powered hydrogen network the infrastructure must be switched over, by means of a gas conversion programme.

As part of the 10-point plan announced by the Prime Minister on 18th November, the government have set the aim of producing a hydrogen heated neighbourhood by 2023, a village by 2025 and a town by the end of the decade.

Find Out More in our 'Hydrogen: The Role of Green Gas in the Decarbonisation of Heat' CPD

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How Heating with Hydrogen Works

The main appliance components as we know today will remain, with the necessary adaptation to operate with hydrogen. Key development challenges are aspects of flame detection, flashback prevention, gas-air control, condensate management, materials compatibility and H2-gas tightness.

Hydrogen compared to today’s boilers

  • Sizing: The appliances will have very similar shape, size and weight as today’s appliances, facilitating the replacement of the old appliances.
  • Usage: The appliances will be connected to the same heating distribution system in the property (radiators, floor heating) and will fulfil the same functions as todays appliances (Space heating and DHW production, in one unit or with the support of external DHW storage).
  • Efficiency: The efficiency level of H2 appliances will be comparable to the current condensing appliances.

Hydrogen and Heat Pumps - what´s the future technology?

We know there is no single solution to heating UK properties and we will require a mix of technologies to manage the energy transition successfully. Green gases such as hydrogen will be part of the mix.

  • Heat pumps and hydrogen boilers will most likely be the devices that will heat and produce domestic hot water for our homes and offices for decades to come.
  • These two technologies will coexist because both will offer their best assets under very specific conditions of use, with their specific limits and advantages.

What We Are Doing to Support You and Your Business



Migration Support

Technical support and Tools

Training for Partners


The Vaillant Group is undertaking research activities in hydrogen-run heating systems. We are developing a 100% hydrogen-run, modulating wall-hung boiler for field testing in 2021.


We involve ourselves in the public hydrogen discussion and keep an open dialogue with all relevant stakeholders because we are convinced that the use of green hydrogen in heating has great benefits. We follow discussions at the regional, national and EU level.

In the UK, we are participating in HyDeploy, a project to test and define the safety of boilers to run on a hydrogen admixture of up to 20%. Since November 2019 the Health and Safety Executive have been monitoring several boilers at Keele University where one boiler is run on Natural Gas and the other is run on an admixture of Natural Gas and up to 20% hydrogen. The project aims to understand whether this admixture is a viable option to cut our carbon emissions in the UK. The next step begins in 2021 where a live test will take place in a real village just south of Gateshead, heating more than 650 homes with an admixture of up to 20% hydrogen. If stage two is successful, the 20% admixture will be rolled out to the rest of the UK starting in the North which could save up to one fifth of greenhouse gasses emitted by homes today.

Migration Support

As a European leader in wall-hung condensing boilers, we will continue to support our installers and specifiers with the conversion to hydrogen, just like we have in the past decade in the migration from non-condensing to condensing boilers.

Technical support and Tools

You can rely on our expertise in more complex technologies like heat pumps and now, hydrogen. We will provide you with all the support needed, including technical advice and tools.

Training for Partners

In the course of our ongoing training programmes, we support installers, architects and planners in becoming experts in hydrogen.

This now includes our accredited CPD Course 'Hydrogen: The Role of Green Gas in the Decarbonisation of Heat'. Find out more here.

What's Next?

It is a long journey towards hydrogen heated properties but that doesn’t mean you can’t start learning about it today. Sign up to our ‘Hydrogen: The Role of Green Gas in the Decarbonisation of Heat’ CPD.

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Find out more about hydrogen and the road to decarbonisation