New Scientist 2018 sep

20 | NewScientist | 8 September 2018

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” by

US president at the time George

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 recent survey 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 40,000

hydrogen vehicles on the road in

the next five years, and South

Korea 16,000. Germany wants to

have 400 refuelling stations for

hydrogen vehicles by 2025 and

California has already opened 35.

This renewed push has its

sceptics. Tesla chief Elon Musk, for

example, has dismissed hydrogen

cars 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.

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, above right).

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

hydrogen gas 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.

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

INSIGHT HYDROGEN CARS

Gassed up and ready to go

Vehicles that run on hydrogen have been dismissed by the likes

of Elon Musk, but they’re making a comeback, says Alice Klein

GETTY

The Toyota Mirai is one of the

first mass-market hydrogen cars

“Hydrogen vehicles

produce zero emissions,

so don’t damage our

health or the climate”