Some technologies are just plain exciting.
A few minutes reading about AI, space travel or nanomedicine
can paint a dazzling picture of
a not too distant future full of technological wonders.
But if such a future is possible,
it will likely owe less to space-age science fiction wizardry
than it will to a technology which already exists.
One that’s been around for quite a while, which we use throughout our daily lives,
and which might seem a little... less exciting.
Batteries.
The modern importance of batteries is obvious.
From talking teddy bears, to electric toothbrushes,
to submarines, to the international space station,
batteries enable huge parts of our world.
And in electric cars, buses, and even planes,
they’re defining the next generation of transport.
But perhaps the most important of these new roles
is the storage of renewable energy.
Because while wind and solar power solutions
take huge strides forward each year, they do still have a pretty big drawback.
The wind isn’t always blowing, and the sun isn’t always shining,
but we need power 24 hours a day.
Enter the humble battery.
In 2017, Tesla won a $90 million contract
to construct a ‘power reserve’ at the Hornsdale Wind Farm in Australia.
The result is a large plot of land,
covered with fridge-sized containers filled with battery cells,
which store energy when surplus amounts are being generated by the wind farm,
and then release it into the power grid when supply is low.
The project’s success has spurred the development of similar facilities
around the world as countries race to meet their commitments to clean energy.
What’s more, there are moves to replicate the idea on a household level,
with “powerwall” technologies
being developed to store excess energy from rooftop solar panels for later use.
The rise of these kinds of systems could represent a huge step
in the efforts to decrease our dependence on fossil fuels,
and they’ve only been made viable by recent technological advances.
Battery performance has steadily improved in recent years,
while the average cost of a battery kilowatt hour
has fallen by an order of magnitude.
And while this is great news, it doesn’t necessarily represent a solution
to all of our energy storage woes.
One problem here is that
as batteries become better and cheaper, we want more of them -
global battery demand is expected to triple between 2020 and 2025,
and this demand is going to be increasingly hard to meet,
especially to supply the level of energy storage required to power a country.
But an even bigger issue is that battery cost really doesn’t scale well.
For devices with relatively low power demands like your phone and laptop,
batteries are a fairly affordable solution, costing, at most,
a couple of hundred dollars.
Whereas a battery like the kind you’d find in an electric car
will cost thousands of dollars
which is pretty expensive, if not prohibitively so.
However if we scale things up to the level of a national grid,
things really start to fall apart.
In one year, the US consumes almost 4000 billion kiloWatt hours,
which means that at 2020 prices,
the cost of powering the US for one day on batteries alone
would be almost 1.5 trillion dollars
or... just over a third of the 2020 US federal budget.
It’s with these issues in mind that
many people are beginning to look further afield for new energy storage solutions,
and it turns out there are quite a few.
Because what’s important to realise
is that batteries only represent one form of energy storage.
For example, around 95% of the world’s current energy storage makes use of
gravitational potential energy,
in a process known as
‘pumped hydroelectric’ storage, or ‘pumped hydro’.
Remember how at the Hornsdale Wind Farm, excess energy was stored in batteries?
Well in pumped hydro, that excess energy is used to pump water uphill,
where it’s stored in a reservoir.
When more power is needed, the water is allowed to flow downhill
- hence the word ‘gravitational’ -
powering turbines and generating electricity.
This is a surprisingly simplistic and effective idea,
though of course it isn’t perfect either -
it takes up lots of space, requires water access and very specific geography.
But the point is that thinking beyond batteries
opens up a lot of new possibilities:
Pumped-Hydro-inspired systems using cranes and concrete weights.
Systems which store energy as heat in carbon blocks.
Compressed air storage.
Cryogenic energy storage!
These are all real projects pursuing alternative solutions to the same problem,
and demonstrating that energy storage is a diverse and constantly evolving field.
And it needs to be.
Because it’s impossible to ignore the extent to which we depend on energy
and how this dependency will grow in the future.
Whether we’re talking about powering your latest handheld device,
the future of clean transport,
or the challenges of infrastructure-scale power grids,
it’s clear that in the coming years,
energy storage is going to be an increasingly important topic.
But it’s essential we realise that there’s no one-size-fits-all solution here.
Batteries will continue to be essential to our everyday lives in many ways,
but the conflict between our rising power usage
and the need to accelerate our transition to sustainable energy
leaves us with an energy-storage void -
one which batteries alone are unlikely to ever fill.