Hydrogen fuel: essential for decarbonisation or “a load of rubbish”?
The UK Government has just announced funding for Europe’s first hydrogen plants, claiming that the new infrastructure “could generate enough clean energy to heat over 200,000 homes”. This is in line with the most recent advice from the Committee on Climate Change (CCC), which recommends investing significantly in hydrogen infrastructure to reach our emissions targets. The CCC says: “Hydrogen has a role in electricity generation, transportation, industry and heating.”
Yet this same fuel source has been described as “a load of rubbish” by Tesla CEO Elon Musk. Never one to think twice before speaking his mind, the electric car entrepreneur refers to hydrogen fuel cells as “fool cells” and has called the whole concept “mind-bogglingly stupid”. So what are the facts about hydrogen fuel?
What is hydrogen and how is it used as a fuel?
Hydrogen is the most abundant chemical in the universe. Under standard temperature and pressure, it takes the form of a gas.
Hydrogen fuel cells take the energy from a chemical reaction between hydrogen and oxygen, and convert it into electricity. As long as there is enough of both elements to keep fuelling the reaction, the cell continues to produce power. Fuel cells first became famous as the energy source for NASA’s rockets in the 1960s, but they have a much wider application in powering cars, buses, forklift trucks and other vehicles. The first commercially mass-produced fuel cell vehicle in the world, the Hyundai Tucson FCEV, has been in production since 2013. Several cities around the world run hydrogen-powered bus services.
Hydrogen also powers some buildings, in the form of stationary fuel cells. These tend to be used either in off-grid areas or as back-up power.
Why use hydrogen fuel?
Hydrogen is seen by many as a “clean” fuel because the only waste products from the chemical reactions taking place in a hydrogen fuel cell are heat and water. This means a hydrogen-powered vehicle won’t pollute the air like a vehicle with a standard combustion engine. It also means that on paper, a hydrogen-fuelled car could be described as “zero emissions” – an extremely desirable quality as we try to reach net zero by 2050.
So hydrogen is a zero-carbon fuel?
Only in theory. It’s true that no carbon emissions are generated when a hydrogen fuel cell creates electricity. But the creation of the cell in the first place is not a zero-emissions process.
The problem is that the hydrogen on Earth isn’t found in its pure gaseous form; it’s locked up in compounds such as water, hydrocarbons, acids and hydroxides. To use the gas as a fuel, we first need to unlock it from those sources.
At the moment, most hydrogen fuel production uses hydrocarbons, also known as fossil fuels. The most commonly used sources are natural gas and coal, and the processes for getting hydrogen out of both of them involve producing waste greenhouse gases. Producing one tonne of hydrogen from natural gas or coal will result in between 7 and 12 tonnes of carbon emissions, depending on the method. Using carbon capture and storage (CCS) cuts down on overall emissions, but the Committee on Climate Change warns that even this doesn’t make it green enough. “Producing large volumes of hydrogen from natural gas with CCS could lock the UK into a path with insufficient emissions reductions [to meet net zero] by 2050.”
Is hydrogen any greener than fossil fuels?
Hydrogen has the highest combustion energy by weight of any fuel, which means a tonne of hydrogen will provide 2-3 times more energy than most other fuels. That higher energy-to-emissions ratio makes it a slightly greener option than fossil fuels.
But the real green potential of hydrogen has yet to be explored. Although over 90% of global hydrogen production involves fossil fuels, it is also possible to produce hydrogen by using a process called electrolysis, where electricity splits water into its component elements of hydrogen and oxygen. If the electricity used is from a renewable source, the hydrogen produced is a truly green fuel. Unfortunately, electrolysis is a lot more expensive than producing hydrogen from hydrocarbons, although costs are coming down as the technology develops.
Is green hydrogen power a realistic option?
The CCC recommends that by 2050, the UK’s hydrogen production capacity should be “of comparable size to the UK’s current fleet of gas-fired power stations”. This would allow us to use hydrogen in shipping, long-distance road transport and buildings. The Government has just allocated £70 million to fund two low-carbon hydrogen production plants in Merseyside and Aberdeenshire. A third project in Lincolnshire will use wind power for electrolysis. If it becomes operational before a similar project announced last month in Belgium, it will be the first commercial-scale project of its type in the world.
But the CCC also says that hydrogen can’t help us get to net zero unless we either find a way to drastically cut emissions from the fossil-fuel method or start producing all our hydrogen through electrolysis. This would be expensive and, even taking into account the new projects just announced, it would be a struggle to build the capacity before 2050. But it is possible that the UK could end up importing hydrogen created by solar-powered electrolysis from countries where solar electricity is very cheap.
It’s difficult to judge the true potential of hydrogen when new developments are happening all the time. One multinational project called STORE&GO has been experimenting with the extraction of hydrogen from renewably sourced methane, using renewably sourced electricity. Pilots in Germany, Italy and Switzerland seem to have been successful so far.
In the UK, Keele University is undergoing the first live trial of hydrogen in a modern gas network. The researchers changed the mix of the university’s gas supply so that it now contains 20% hydrogen. This has reduced emissions without making any difference to the existing pipes or appliances – and the kitchen staff haven’t noticed the difference. If this change was applied to our entire gas network, it would reduce our emissions by six million tonnes.
However, despite recommending the use of hydrogen in many sectors, the CCC is cautious about treating it as the answer to our decarbonisation problems. Their most recent specialist report on the subject states: “We conclude that hydrogen is best used selectively…This means using hydrogen where the alternative is continuing to burn unabated fossil fuels.” Not exactly a miracle solution…but not a “load of rubbish” either.