Hannah Smith
Renewable energy technologies like solar, wind and hydro are Scotland’s
largest source of electricity.
They provide more of our electricity that coal, gas and nuclear, and
displace the equivalent of the emissions from every car, van, bus and train
in our country every year.
But renewables, just like gas, coal and nuclear, have limitations.
Our demand for energy has always fluctuated throughout the day, month and
year, and meeting those demands while using clean energy technologies to
help tackle climate change – and against that backdrop of changing
generation patterns – means asking more and more of an energy system with
its roots in the 1930s.
Some critics argue that renewables, despite their tangible benefits, cannot
make a significant contribution to our energy mix because the energy they
supply doesn’t necessarily correlate with demand.
Sometimes it’s very windy, or very sunny, so we can generate huge amounts
of energy – but it may be at a time when there isn’t any need for it. For
example, wind turbines generating electricity in the middle of the night.
Energy supply and demand, though, aren’t static, so our energy system needs
to evolve. Already, National Grid have said the idea of “baseload” power,
whereby power stations must run 24-7, is “outdated”. But there’s an ace in
the hole which could see renewables’ share of our energy mix increasing
dramatically: energy storage.
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Storage can take the energy created by renewables at times when it’s not
needed, or when bottlenecks on the grid mean it can’t get to consumers, and
save it for later. Neither storage nor renewables are perfect on their own,
but both can work together to produce a result far more powerful than the
sum of their parts.
At a local level, household batteries like Tesla’s Powerwall can provide
energy solutions for homes and businesses – for example storing daytime
energy from solar panels to be used during dark winter evenings, when
demand is highest, saving money on electricity which has to be bought in
from the grid. Not only does this mean renewables are used to their full
potential; it also gives consumers better control and flexibility over how
they manage their energy.
But storage isn’t all about electricity. Thermal stores can absorb and
release heat on demand. That heat can be generated from various sources
including solar energy and then stored in water, molten minerals, clay or
banks of earth.
Sainsbury’s supermarket in East Kilbride installed a system to take heat
from in-store freezers, push it into rocks deep underground, then recover
it later to warm the store in colder seasons. Increased use of technology
like this could give a value to excess heat created by supermarkets, data
centres and shopping malls, rather than using electrical refrigeration to
transfer it uselessly into the atmosphere.
Storage can also mean creating hydrogen gas from electricity. In Methil,
Fife, a five-year project to run vehicles on hydrogen produced using wind
and solar power is underway, with backers including electronics giant
Toshiba, which is using the site as its first hydrogen research project
outside Japan.
Hydrogen and wind fit perfectly together, and teaming hydrogen fuel cells
with wind power creates portable energy when we can’t immediately use the
electricity the wind power provides. Hydrogen can be supplied through
underground pipes like conventional gas, and used in its place for cooking
and heating, as well as to power a fuel cell to create electricity, as in
Fife.
While renewables and storage are complementary, there are other benefits
too: reducing the need to invest in power transmission infrastructure and
increasing the security and certainty of our energy supply, for example.
The advent of storage technologies will only increase the speed at which
our energy system is changing. A real 21st century system will integrate
different energy sectors (electricity, heat and transport), while increased
household energy control will put people right at the centre of how we
create and use power.
Underneath all this lies an imperative. We need to reduce carbon emissions.
We must generate clean, secure energy in a way that responds to this
changing system, and in a way that makes sense for consumers.
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Storage technologies are central to that. They will help us get the most
out of our renewable energy sources, and combined storage and renewables
are the key to our energy future.
Hannah Smith is a policy officer with Scottish Renewables.
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