85% of British homes rely on gas central heating. We’ve been discussing the benefits of heat pumps recently in our community and on our blog. In addition to electrifying home heating, introducing low-carbon gases like hydrogen are an important part of the UK’s heat decarbonisation strategy, especially where electrification is difficult or impossible but, is hydrogen the solution to net-zero home heating?
Hydrogen and energy have a long shared history, right from powering the first internal combustion engines over 200 years ago. It is:
the simplest and most abundant element known
an energy carrier rather than an energy source
a colourless, odourless and highly combustible gas
Petroleum and fertiliser production are the largest uses of hydrogen currently, but transportation and utilities are emerging industries in using the gas. It has the potential to generate 44TWh (1TWh= 1,000,000,000,000 Wh), avoiding 6% of heat emissions, in 2050.
Demand for hydrogen has grown more than threefold since 1975.
Global demand for pure hydrogen, 1975-2018
Hydrogen can be produced using different resources, but it is currently generated mostly from fossil fuels.
Currently, 6% of global natural gas and 2% of global coal are going to hydrogen production but dedicated electricity generation from renewables offer an alternative.
Hydrogen can be produced using a number of different processes.
- Electrolysis - separating the molecule H20 into oxygen and hydrogen
- Biological - microbes like bacteria and microalgae consume plant material and produce hydrogen
- Natural gas reforming - a mixture of hydrogen, carbon monoxide, and carbon dioxide is created by reacting natural gas with high-temperature steam.
Based on the process used, the product is given one of the following names:
Produced industrially from natural gas, generating significant carbon emissions which aren’t captured.
Produced when natural gas is split into hydrogen and carbon dioxide. The carbon emissions can be captured and stored, or reused.
Green hydrogen is the cleanest option and is produced through electrolysis (i.e. separating water into hydrogen and oxygen). This electrolysis is powered by electricity from renewable energy sources.
Currently, grey hydrogen is cheaper than blue and green hydrogen. This might change as natural gas prices become more volatile and carbon pricing increases around the world.
Blue hydrogen can’t play a significant role in the decarbonisation of heat without a greater roll out of carbon capture, utilisation and storage (CCUS) infrastructure, and the availability of affordable ‘green’ hydrogen is still some way off.
In his Ten Point Plan, Prime Minister Boris Johnson listed ‘driving the growth of low carbon hydrogen’ at number two. The UK is aiming for 5GWh (1 GW= 1,000,000,000 and the equivalent of 110 million LEDs) of low carbon hydrogen production capacity by 2030.
There are several pilot hydrogen schemes in development around the UK.
So, the development of hydrogen is still small-scale. According to a survey by Hydrogen Strategy Now, 78% of industry leaders believe the 5GW hydrogen production target set out in the PM’s Ten Point Plan could be more ambitious.
The degree to which energy suppliers will be able to supply zero carbon heating to UK homes will depend largely on the level of support these technologies receive.