HYDROGEN-POWERED cars have had a bumpy ride. Back in 2003, they were touted as “one of the most encouraging, innovative technologies of our era” W. Bush. Then the Tesla revolution came along and they were left in the dust by their battery-driven electric rivals.
Now, there are signs of a comeback. A of more than 900 global automotive executives by consulting firm KPMG found that 52 per cent rated hydrogen fuel cell vehicles as a leading industry trend. Japan has announced plans to put , and South Korea wants to have vehicles by 2025 and California has already .
This renewed push has its sceptics. Tesla chief Elon Musk, for example, has as being “extremely silly”. But Joan Ogden at the University of California, Davis, sees a future in which hydrogen and electric vehicles play complementary roles. “There are arguments for having both,” she says.
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Like electric cars, hydrogen vehicles produce zero pollutants and carbon emissions, so they don’t damage our health or the climate. The main difference is that hydrogen cars use a fuel cell instead of a battery to power an electric motor. Hydrogen is stored in a tank and fed into the fuel cell, where its chemical energy is converted into electrical energy (see “diagram”).
Hydrogen cars are finally becoming commercially viable because fuel cells have become smaller and lighter, says Matthew Macleod at Toyota, which began selling the Mirai, one of the first mass-market hydrogen cars, in 2014 for $60,000. Honda and Hyundai have competing models, and Mercedes-Benz plans to launch one next year.
We are also figuring out better ways to transport and store hydrogen, says Michael Dolan at Australia’s national science organisation, the CSIRO. Last month, his team showed that can be converted to liquid ammonia for transportation, then converted back using a membrane made from the metal vanadium. Liquid ammonia takes up less space and is less flammable than hydrogen gas, making it easier to ship to refuelling stations.
“Hydrogen vehicles produce zero emissions, so don’t damage our health or the climate”
The ability to rapidly refuel is one of the main advantages hydrogen vehicles have over their electric counterparts, says Macleod. Filling up a hydrogen car takes about the same time as filling a petrol one, rather than the hours it typically takes to recharge an electric car’s battery. You can also go further on a full tank of hydrogen – about 500 kilometres, compared with 300 kilometres for a standard fully charged battery (see Table).
But although hydrogen reacts cleanly – the only thing coming out of the exhaust pipe is water – hydrogen vehicles are more energy-intensive than electric ones if you factor in fuel production and transport, says Jake Whitehead at the University of Queensland, Australia.
Clean fuel?
At the moment, most hydrogen is extracted from natural gas – a fossil fuel. “Green” hydrogen can be made by splitting water using solar or wind power, but this involves multiple steps, each using energy along the way. In contrast, a single energy step is required to directly recharge a car battery at home.
If you account for this complete energy cycle, Whitehead’s modelling shows that hydrogen vehicles require between 80 and 100 kilowatt-hours of electricity to travel 100 kilometres, compared with about 20 kilowatt-hours to travel the same distance in a battery vehicle. This is the main charge levelled by Musk at hydrogen cars. “[The efficiency is] terrible, so why would you do that? It make no sense,” he .
Hydrogen fuel is also more expensive than petrol. Hydrogen cars currently cost about 13 cents per kilometre to run, compared with 8 cents per kilometre for petrol cars. However, some projections suggest that the costs will as the technology to produce hydrogen becomes cheaper.
At the moment, there are only about 6000 hydrogen vehicles on the road globally, compared with 2 million electric vehicles. But Ogden says that hydrogen vehicles may end up becoming more popular among certain drivers. “If you’re only using your car for short commutes or to get around the city, battery cars can handle all your needs,” she says. “But if you want a big car that you can take on long drives in the mountains on a whim, a hydrogen fuel cell car might be better.”
The shorter refuelling time and longer range of hydrogen fuel cells also make them appealing for taxis, buses and long-haul trucks, says Dolan. “These vehicles can’t afford to be stopping for hours at a time to recharge,” he says.
Hydrogen fuel cells are already finding applications in these heavy-use vehicles. Japan will showcase , and South Korea plans to introduce . A fleet of , private-hire and police cars is being trialled in London, Paris and Brussels, and retailer Amazon has recently invested in . US manufacturer Nikola Motors, meanwhile, says it has received .
Japan and South Korea are leading this push because they want to embrace zero-emissions technology, but their combination of small land masses and large populations means they don’t have enough solar, wind or other renewable energy to support large numbers of battery electric vehicles, says Dolan.
They can’t import renewable energy itself, but they can import hydrogen made from renewable energy in other countries. Australia, for example, could use its abundant solar energy to split water and export hydrogen to these countries, says Dolan. “You can see hydrogen basically as a carrier for renewable energy.”
“There are only about 6000 hydrogen vehicles on the road globally, versus 2 million electric vehicles”
Many people feel jittery about hydrogen because of its connection with hydrogen bombs and the 1937 Hindenburg disaster, in which a hydrogen-filled airship spectacularly caught fire, killing 36 people. But the hydrogen tanks used in modern fuel cell vehicles are made from multiple layers of resin, carbon fibre and fibreglass that keep the flammable gas safely contained. Tests show they can even survive being shot at or set on fire. New ways of transporting hydrogen – like in the form of ammonia – will also make its deployment safer, says Macleod.
The most probable future scenario is that we will have a mix of vehicles run by batteries, hydrogen and petrol, each performing different roles, says Ogden. “There are proponents of the different technologies saying it’s all going to be all hydrogen or all batteries, but auto-makers are putting their money on both,” she says. According to the KPMG survey, car-makers are predicting an , hydrogen, petrol and hybrid vehicles by 2040.
The final mix will depend on the willingness of governments and industry to invest in hydrogen infrastructure – for example, by building refuelling stations and introducing hydrogen buses – as well as consumer enthusiasm for hydrogen cars. But whether it ends up being hydrogen or battery power that wins the bigger share, any dent in the dominance of petrol vehicles is likely to be a good thing. With less emitted carbon warming our globe, less toxic exhaust fumes choking our lungs and less smog staining our skylines, we will all be better off.
This article appeared in print under the headline “Gassed up and ready to go”
