There’s a high cost to capturing the most abundant element
The UK has claimed a world first with the construction of two seemingly ordinary semi-detached homes in Gateshead in the north-east of England. They look like any other new build but all the appliances run on hydrogen.
The government’s All Party Parliamentary Group on Hydrogen produced a report claiming “hydrogen is the solution to decarbonisation in industry, power, heat and transport”. Momentum is building around hydrogen as a ‘carbon-free’ alternative to natural gas for domestic, transport and industry energy use.
Last year, Daimler and Volvo joined forces to develop a hydrogen fuel cell for long-haul vehicles and, in the same year, a hydrogen-powered train made its maiden journey in the UK. A partnership of Danish companies, including Maersk and Scandinavian Airlines, is aiming to have a hydrogen and e-fuel production facility operational by 2023 to power buses, trucks, maritime vessels and aeroplanes.
Meanwhile, Neom, Saudi Arabia’s planned futuristic city, hopes to house the world’s largest hydrogen plant in a bid to run itself on 100% renewable energy with zero emissions. And Unilever is taking part in what is claimed to be a world-first pilot, funded by the UK government, to demonstrate how hydrogen can be used at an industrial scale. The firm’s Port Sunlight factory and glassmaker Pilkington will test how hydrogen can be substituted for natural gas in manufacturing processes.
The problem of obtaining hydrogen
The benefits of hydrogen are straightforward – it gives off no CO2 when it burns and produces only water. However, what is less obvious is sourcing the energy required to produce it.
Hydrogen is the most common and lightest element, making up an estimated 75% of the universe, though on earth it exists only in compounds where it is joined to other elements. Hydrogen must be separated from these elements and there are three main ways to do this.
‘Grey’ hydrogen is made by separating it from methane or coal, which is how 98% of hydrogen is currently made. The process is energy intensive as for every tonne of hydrogen produced from gas, 10 tonnes of CO2 are emitted, while for coal, 19 tonnes of CO2 are released, according to Simon Pirani, senior research fellow at the Oxford Institute for Energy Studies.
The International Energy Agency (IEA) says 6% of global natural gas and 2% of coal goes towards hydrogen production, resulting in CO2 emissions of around 830m tonnes each year, equivalent to the CO2 emissions of the UK and Indonesia combined.
‘Blue’ hydrogen is made in the same way but carbon-capture technology is used to limit emissions. Pirani says although this is straightforward for around 70% of emissions, above 85% it “gets really tricky”.
‘Green’ hydrogen uses renewable energy to split it from water using electrolysis, which is even more energy intensive than the other methods. According to an IEA report in 2019, 0.1% of hydrogen is made this way.
“Producing all of today’s dedicated hydrogen output from electricity would result in an electricity demand of 3,600TWh [terawatt hours], more than the total annual electricity generation of the EU,” the IEA says.
Find the perfect blend
For hydrogen to become a viable alternative to natural gas, far more renewable energy infrastructure and capacity is required. Around 87m tonnes of hydrogen were produced globally in 2020 but this would need to reach 212m tonnes by 2030 if climate goals are to be achieved, according to the IEA.
The HyDeploy pilot study at Keele University, which began in 2019, supplied faculty buildings and 100 homes with a mix of natural gas and 20% hydrogen and was hailed a success earlier this year.
Steve Fraser, chief executive at gas firm Cadent, part of HyDeploy, says the trial showed that “consumers can safely receive up to 20% hydrogen blended with natural gas without the need to make any changes to their existing appliances”.
HyDeploy says if this blend were used across the UK, it could save around 6m tonnes of CO2 emissions each year. Currently the law only permits a blend of 0.1% hydrogen in gas networks.
However, Pirani argues: “Why would you even think about using hydrogen to heat people’s homes when technologies that work and are already in use – retrofitting electricity and heat pumps – could do the job better? You wouldn’t. Unless you were seeking ways of wringing the last few bits of profit out of oil and gas production.”