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 our homes.

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

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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.

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.

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: C02 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: C02 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 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. A blend of 20% hydrogen mixed with natural gas could give us a saving of up to 7% CO2 when using green hydrogen. 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.

(source https://www.gov.uk/government/news/pm-outlines-his-ten-point-plan-for-a-green-industrial-revolution-for-250000-jobs )

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.

Vaillant is developing hydrogen burning appliances which look and feel the same as today’s boilers, eliminate CO2 emissions, and have better NOx performance. The hydraulic components within the hydrogen boiler will also be the same as today, the only change will be with the combustion cell.

Although the future of home heating is fast changing we do not expect to see a mass roll out of hydrogen boilers until the early 2030’s as it is unlikely that homes, which are currently on the gas grid, will have a hydrogen supply to their doorstep much before then. Hydrogen ready and 100% hydrogen boilers come at a cost premium to the end user, until manufacturers can build at significant scale. For some installations there will be no tangible benefit of their wall hung boiler being hydrogen ready as they may never see hydrogen in their lifetime. For hydrogen boilers to be rolled out before this date we would need hydrogen to be mandated with the fuel cost to the end user clearly defined. Urgency on decision making is key here, there are approximately 1.6 million new boilers installed each year, and therefore Vaillant estimate it would take over 16 years for fossil fuel boilers to be phased out of the housing stock. The quicker we start this transition, the sooner we will start on our path to achieving our net zero targets.

It is a long journey towards hydrogen heated homes but that doesn’t mean you can’t start learning about it today. Sign up to our dedicated online training course on the role of hydrogen in heating.

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