At the turn of the 20th Century,
Thomas Edison invented a battery with the unusual quirk of producing
hydrogen. Now, 120 years later, the battery is coming into its own.
Traveling
down a gravelly road in West Orange, New Jersey, an electric car
sped by pedestrians, some clearly surprised by the vehicle's roomy
interior. It traveled at twice the speed of the more conventional
vehicles it overtook, stirring up dust that perhaps tickled the
noses of the horses pulling carriages steadily along the street.
It was the early 1900s, and
the driver of this particular car was Thomas Edison. While
electric cars weren't a novelty in the neighborhood, most of them
relied on heavy and cumbersome lead-acid batteries. Edison had
outfitted his car with a new type of battery that he hoped would
soon be powering vehicles throughout the country: a nickel-iron
battery. Building on the work of the Swedish inventor Ernst
Waldemar Jungner, who first patented a nickel-iron battery in
1899, Edison sought to refine the battery for use in automobiles.
Edison claimed the
nickel-iron battery was incredibly resilient, and could be charged
twice as fast as lead-acid batteries. He even had a
deal in place with Ford Motors to produce this purportedly
more efficient electric vehicle.
But the nickel-iron battery
did have some kinks to work out. It was larger than the more
widely used lead-acid batteries, and more expensive. Also, when it
was being charged, it would release hydrogen, which was considered
a nuisance and could be dangerous.
More than a century
later, engineers would discover
the nickel-iron battery as something of a diamond in the rough.
Unfortunately, by the time
Edison had a more refined prototype, electric vehicles were on the
way out in favour of fossil-fuel-powered vehicles that could go
longer distances before needing to refuel or recharge. Edison's
deal with Ford Motors fell by the wayside, though his battery
continued to be used in certain niches such as railroad signaling,
where its bulky size was not a hindrance.
But more than a century later, engineers would rediscover the
nickel-iron battery as something of a diamond in the rough. Now it
is being investigated as an answer to an enduring challenge for
renewable energy: smoothing out the intermittent nature of clean
energy sources like wind and solar. And hydrogen, once considered
a worrisome byproduct, could turn out to be one of the most useful
things about these batteries.
What used to be a dangerous
quirk of the Edison battery has turned out to be remarkably useful
(Credit: Alamy)
Speeding forward to the mid
2010s, a research team at the Delft University of Technology in
the Netherlands happened upon a use for the nickel-iron battery
based on the hydrogen produced. When electricity passes through
the battery as it’s being recharged, it undergoes a chemical
reaction that releases hydrogen and oxygen. The team recognised
the reaction as reminiscent of the one used to release hydrogen
from water, known as electrolysis.
"It looked to me like the chemistry was the same," says Fokko
Mulder, leader of the Delft University research team. This
water-splitting reaction is one way hydrogen is produced for use
as a fuel – and an entirely clean fuel too, provided the energy
used to drive the reaction is from a renewable source.
Nickel-iron batteries are extremely durable, as Edison proved in
his early electric car, and some have been known to last upwards
of 40 years
While Mulder and his team knew that the nickel-iron battery’s
electrodes were capable of splitting water, they were surprised to
see that the electrodes started to have a higher energy storage
than before hydrogen was being produced. In other words, it became
a better battery when it was used as an electrolyser too. They
were also surprised to see how well the electrodes held up to the
electrolysis, which can excessively tax and degrade more
traditional batteries. "And, of course, we were rather content
that the energy efficiency appeared to be good during all this,"
says Mulder, reaching levels of 80-90%.
Conventional electrolysers are
employed to convert renewables to hydrogen, but Mulder hopes the
battolyser could do this more efficiently and cheaply
(Credit: Getty Images)
Mulder dubbed their
creation the "battolyser", and they hope their discovery
can help solve two major challenges for renewable energy:
energy storage and, when the batteries are full,
production of clean fuel.
"You'll hear all these
discussions about batteries on the one hand and hydrogen
on the other hand," says Mulder. "There's always been a
kind of competition between those two sets of directions,
but you basically need both."
Renewable
value
One of the biggest
challenges of renewable energy sources such as wind and
solar is how unpredictable and intermittent they can be.
With solar, for example, you have a surplus of energy
produced during the daytime and summertime, but at night
and in the winter months, the supply dwindles.
Conventional
batteries, such as those based on lithium, can store
energy in the short-term, but when they’re fully charged
they have to release any excess or they could overheat and
degrade. The nickel-iron battolyser, on the other hand
remains stable
when fully charged, at which point it can transition
to making hydrogen instead.
"[Nickel-iron
batteries] are resilient, being able to withstand
undercharging and overcharging better than other
batteries," says John Barton, a research associate at the
School of Mechanical, Electrical and Manufacturing
Engineering, Loughborough University in the UK, who also
researches battolysers. "With hydrogen production, the
battolyser adds multi-day and even inter-seasonal energy
storage."
Besides creating
hydrogen, nickel-iron batteries have other useful traits,
first and foremost that they are unusually
low-maintenance. They are
extremely durable, as Edison proved in his early
electric car, and some have been known to last upwards of
40 years. The metals needed to make the battery – nickel
and iron – are also more common than, say, cobalt which is
used to make conventional batteries.
This means the
battolyser could have another possible role for renewable
energy: helping it become more profitable.
Like any other
industry, renewable energy prices fluctuate based on
supply and demand. On a bright, sunny day there might be
an abundance of power from solar, which can lead to a glut
and a dip in the price the energy can be sold for. The
battolyser, however, could help smooth out those peaks and
troughs.
"When electricity
prices are high, then you can discharge this battery, but
when the electricity price is low, you can charge the
battery and make hydrogen," says Mulder.
The battolyser is one way to help balance the supply and demand of
renewable energy from sources like solar and wind (Credit:
Alamy)
The battolyser is not alone in
this regard. More traditional alkaline electrolysers coupled with
batteries can perform this function too, and
are widespread in the hydrogen-producing industry. Mulder
thinks the battolyser can do the same thing for less money and for
longer, thanks to the durability of the system. It is something
that is making the battolyser's backers hopeful.
And while hydrogen is the
direct product of the battolyser, other useful substances can be
generated from it too, such as ammonia or methanol, which are
typically easier to store and transport. "Having a battolyser in
place, [an] ammonia plant would run more constantly and [would]
need less manpower, reducing operating costs and maintenance
costs, thus producing ammonia the cheapest way in a sustainable,
green manner," says Hans Vrijenhoef, chief executive of Proton
Ventures, who has invested in Mulder's battolyser.
Scaling up
Right now, the largest
battolyser in existence is 15kW/15kWh, and has enough battery
capacity and long-term hydrogen storage to power 1.5 households. A
larger version of a 30kW/30kWh battolyser is in the works at the
Magnum power station in Eemshaven in the Netherlands, where it
will provide enough hydrogen to satisfy the needs of the power
station.
Once it's undergone
rigorous testing there, the aim is to scale-up further and
distribute the battolyser to green energy producers, such as solar
and wind farms. Ultimately, the battolyser's proponents hope it
will reach gigawatt-scale – equivalent to the power generated by
around
400 utility-scale wind turbines. Though as well as scaling-up,
Barton sees a role for smaller battolysers, which could help
supply energy to mini-grids used by remote communities that don't
live on main power grids.
Edison's laboratory in New Jersey
was the birthplace of many of his inventions, both those that gained
popularity in his lifetime and those that didn't (Credit:
Alamy)
The fact that the battolyser's
electrodes are made from relatively cheap and common metals may help. And
unlike lithium, nickel and iron do not create large quantities of water
waste when mined, nor are they linked to
significant environmental degradation.
Still, both Mulder and Barton see
hurdles to overcome in terms of efficiency and capacity. "The battolyser
would really benefit from increased power capacity as a battery, or
reduced internal resistance," says Barton. Internal resistance is the
opposition to the flow of current in a battery. The higher the internal
resistance, the lower the efficiency. Improving that is something Mulder
and his team are now working on.
Much of the potential of the
battolyser has been hiding in plain sight, ever since Thomas Edison first
began experimenting with his nickel-iron battery at the turn of the 20th
Century. He may have been wrong in believing his battery would supplant
the other vehicles on the road. But the nickel-iron battery may yet play a
role in replacing fossil fuels more broadly, by helping hasten the
transition to renewables.--
