Hydrogen is regularly discussed as a form of low carbon heating. Theoretically, hydrogen can be transported using existing gas infrastructure. For this reason, hydrogen has been viewed as a good low-carbon alternative. There are several ways of producing hydrogen gas, discussed further below, and each have different carbon intensities. Therefore, how we produce hydrogen for heating has a huge impact on the sustainability and feasibility of switching to hydrogen.
Using current gas infrastructure
There are constraints with using current gas infrastructure. Being such a light gas, hydrogen can react with the metal pipes and cause the metal to degrade. This will result in leaks of hydrogen and inefficiencies in the system. Many of the pipelines in the UK have already been futureproofed against this by switching to a yellow polyethylene material. However, there is still a considerable amount of work to be done before hydrogen can be transported safely through the network.
Producing hydrogen gas is energy intensive and can release carbon, making it counterintuitive to switch to this type of hydrogen to achieve net-zero carbon. However, hydrogen can be produced carbon-neutrally. The different forms of hydrogen fuel are:
- Brown hydrogen – produced from coal gasification
- Grey hydrogen – produced from natural gas
- Blue hydrogen – produced from non-renewable sources but utilises Carbon Capture and Storage (CCS) to capture around 90% of emissions, making it more expensive
- Green hydrogen – uses renewable energy to produce the fuel
It is evident that green hydrogen would be the net-zero carbon option. However, currently 96% of hydrogen produced is grey hydrogen and releases ~9 tonnes of CO2 per tonne of hydrogen gas. To scale up green hydrogen, we would require a significant reduction in the production cost and expansion of renewable energy. At the moment it is an expensive option due to costs of renewable electricity and the need for battery storage. However, hydrogen can only be seen as a viable alternative in a net zero carbon economy if it is produced from low-carbon sources. This raises concerns that by focusing on hydrogen we are putting off investment in renewables, which are more sustainable options for achieving net zero.
What do the Committee on Climate Change say?
The Committee on Climate Change (CCC) state that heat pumps and low-carbon hydrogen are the main options for decarbonising buildings. The CCC suggest that hydrogen is the more attractive alternative as heat pumps are difficult to deploy widely and will require more behavioural change from customers. However, to produce hydrogen in a low carbon way requires CCS which remains undeveloped in the UK and may constrain the areas that are suited to hydrogen. The CCC see a future based on heat pumps, hydrogen and low-carbon heat networks which will only be realised with strong Government leadership. Additionally, they suggest that hydrogen could be more useful in industrial sectors and for HGV transport.
Hydrogen heating in practice
The Government’s hydrogen strategy was due to be published this spring. This will set out a vision of hydrogen’s role in meeting net-zero carbon with regulations and funding to develop hydrogen’s role over the next decade. The H21 project in Yorkshire is a pilot scheme to switch the gas grid to hydrogen and supply heating to 3.7 million homes/businesses by 2035. Whilst this, and other schemes announced in the hydrogen strategy will take a step to reducing carbon emissions, we believe there should firstly be a focus to retrofit fabrics in buildings and reduce the demand for heat before switching the heating type.
To find out more about how you can decarbonise your buildings, or for a roadmap to net zero, get in touch here.