Is Switching to a Hydrogen Gas Grid a Viable Option?
With carbon targets in place, the UK is looking for a low carbon alternative to using natural gas for home heating.
One of the recommended options is to convert the gas network to hydrogen – an efficient gas that doesn’t emit carbon. There are plans to head towards a future where hydrogen makes up 20-35% of UK energy consumption by 2050. But nothing is yet set in stone.
So, is switching to a hydrogen network a viable option? Let’s find out.
Why switch from natural gas?
Burning natural gas to heat our homes now contributes a third of total UK carbon emissions. Mainly because more than 80% of homes in the UK have a gas boiler. So if the UK is to reach targets of reducing carbon emissions by 80% (compared with the levels in 1990) we need to find an alternative way of heating our homes.
One option is a renewable heating system which, rather than burning gas, takes energy from sustainable sources:
Yet, having one of these heating systems installed would come at a cost to the homeowner. This is a large hurdle to overcome, even despite energy bill savings and payments through the Renewable Heat Incentive. Homeowners would also have to learn how to use an unfamiliar heating system.
Another alternative would be switching the gas network to hydrogen.
The Committee on Climate Change (CCC) make recommendations to the government on how best to lower carbon emissions. In a report they released in 2018, the CCC made the case for replacing natural gas with hydrogen. And hydrogen is a gas that offers a number of benefits in terms of home heating:
- Highly efficient (1kg of hydrogen can produce as much energy as 2.8kg of natural gas)
- No carbon emissions from hydrogen boilers (only produce water vapour and heat)
- Can be used in current gas network
- Boilers are a familiar heating system for homeowners, unlike renewable heating systems (heat pumps and solar)
However, switching the entire gas network from natural gas to hydrogen wouldn't be a simple process. The millions of natural gas boilers currently installed across the UK would need replacing with 'hydrogen-ready' units and while this would come at a cost, the CCC stated that it is one of the least costly solutions.
Worcester Bosch revealed their very first hydrogen-ready boiler in 2019, showing the direction that one of the leading boiler manufacturers believe the future of home heating looks like. They were soon followed by Baxi too.
The boiler is still compatible with natural gas but after a short visit from a heating engineer it can work on a 100% supply of hydrogen. This means that the unit can be installed ahead of time but is ready should the gas network work make a switch to hydrogen.
Worcester believe that it is essential for new boilers to be hydrogen-ready, stating that any boiler installed from 2025 should be able to heat a home using hydrogen.
While condensing gas boilers can’t run on 100% hydrogen, many will work on a hydrogen-blend.
What is hydrogen blending?
If the gas network were to switch from natural gas to hydrogen, it wouldn't happen over night.
Instead, it's much more likely that hydrogen would be gradually added to existing gas supply – known as hydrogen blending. Even making the existing gas supply 20% hydrogen would in itself help to cut UK carbon emissions by 6 million tonnes per year (the same as removing the emissions of 2.5 million cars from the road).
Interested in a renewable heating system?
Trialling a hydrogen network
HyDeploy launched a trial of delivering a hydrogen blend to properties in Keele, Staffordshire. During the trial, a 20% hydrogen blend is being delivered to 100 homes and 30 faculty buildings.
Cadent, a gas distribution firm involved in the HyDeploy trial, believe that delivering a 20% blend of hydrogen to the entire gas network would be like taking 2.5 million cars off the road. And reduce UK carbon emissions by 6 million tonnes.
By the end of 2020, it's hoped that a new HyDeploy pilot will launch in the north east of England.
Speaking about the trial, Cadent Chief Safety and Strategy Officer, Ed Syson said: “Hydrogen can help us tackle one of the most difficult sources of carbon emissions – heat. This trial could pave the way for a wider roll out of hydrogen blending, potentially enabling us to begin cutting carbon emissions from heat by the early 2020s, without customers needing to change their gas appliances or behaviour.
“HyDeploy could also prove to be the launchpad for a wider hydrogen economy, fuelling industry and transport, bringing new jobs and making Britain a world-leader in this technology. Urgent action is needed on carbon emissions and HyDeploy is an important staging post on that journey in the UK.”
What are the limitations of hydrogen?
First and foremost, hydrogen is currently an expensive fuel to produce. And while hydrogen can be produced in a number of ways, including electrolysis (splitting water into hydrogen and oxygen using electricity) and Steam Methane Reforming (natural gas reacts with steam, oxygen or both), it can emit carbon.
Green hydrogen is the cleanest form of hydrogen. It’s made when the electricity supplied for electrolysis comes from renewable energy sources (wind and solar). Rather than by burning fossil fuels. An alternative (and most likely route) is blue hydrogen, formed through Steam Methane Reforming but the carbon is captured and stored, known as Carbon Capture Utilisation Storage (CCUS).
While production can produce carbon, once delivered to the boiler, hydrogen won't release any carbon into the atmosphere.
Find out more in Hydrogen Boilers: An Alternative to Gas Central Heating?.
CCUS stands for Carbon Capture Utilisation Storage.
Essentially, this is a way of stopping any carbon made from hydrogen production making its way into the atmosphere. Once stored, it can then be use by other industries. Like adding fizz to drinks.
UK government is looking to make four CCUS sites by 2030. These will be in off-shore gas and oil fields that are no longer used.
The hydrogen made in this way is known as blue hydrogen. One of many colours of hydrogen which all make up the hydrogen rainbow.
You may also come across the term CCS which is the same but the captured carbon isn’t used for anything.
UK Hydrogen Strategy
In 2021, the UK government published their Hydrogen Strategy.
This strategy sets out what the transition to hydrogen will look out. However, there’s no commitment to hydrogen playing a part in the future of home heating. A final decision will be made in 2026.
Until then, boiler manufacturers are making sure their current gas boilers run on a hydrogen blend. Find out which are hydrogen certified in Hydrogen Boiler Manufacturers.
So, is hydrogen a viable option?
According to industry experts, hydrogen has a major role to play in the future of home heating. But it can't be the only solution.
The ideal low-carbon heating system for homes of the future would include a renewable heating system, powered by electricity, alongside a hydrogen boiler.
Unfortunately, hydrogen production is currently very expensive. And those costs are standing in the way of a solution that holds the most potential for decarbonising the UK gas network.
Should the hydrogen trials around the UK go successfully then that will only strengthen the case for a hydrogen network.