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LEADING THE CHARGE
Rapid advances in technology mean that
battery storage is becoming an integral
part of solar PV systems. Glenn Platt of
CSIRO reviews the sector.
Until recently, one of the well-known ‘facts’
regarding the electricity industry was the
impossibility of large-scale energy storage.
At the very least, it wasn’t economically
viable. Without storage, at any instant in time,
complex systems would be needed to ensure
electricity supply was very carefully matched to
demand, or the lights would literally go out.
However, things are changing dramatically,
and large-scale electricity storage will soon be
commonplace. A household battery system
made by Tesla has been installed in a suburban
house in western Sydney.
Tesla is one of the world’s largest
manufacturers of electric cars – in 2015 it sold
about 50,000 cars, which are now able to
drive autonomously.
The head of Tesla established PayPal and
also runs a company that supplies rockets to
the International Space Station, so he is well
known for his success.
Half a dozen other large companies produce
batteries designed for Australian houses and
other buildings, and utilities are rolling out
larger-scale battery storage systems to
support their networks.
What we once considered a ‘fact’ is now
a myth, and large-scale electricity storage is
possible and economical.
What’s changed?
Using large-scale batteries to store electricity
isn’t particularly new.
However, such systems – usually based
on lead-acid batteries – were bulky, required
careful safety procedures and regular
maintenance, and were very expensive.
They were limited to quite niche applications:
for example, providing back-up power in
telephone exchanges, or supporting off-grid
power systems in very remote areas.
As far as residential battery systems go,
these were limited to crazy enthusiasts –
typically old men with beards driving beaten-up
old Land Rovers and living in mud-brick houses.
For batteries to be at the point of becoming
commonplace in our houses and buildings,
some significant changes have occurred:
s
The price of battery systems has fallen
about 70% in the past five years, and
continues to fall.
s
Australian electricity prices have risen more
than 70% between 2007 and 2013.
s
The price of solar generation systems has
dropped dramatically, to the point where
the price of electricity from rooftop solar is
competitive with the retail price of electricity
from the grid. Batteries can now be charged
by cheap, self-supplied electricity.
Although these changes have occurred
worldwide, some additional matters are unique
to Australia.
This country will probably be the first in
the world to experience the mass uptake of
distributed battery systems, because:
s
The incentives or feed-in tariffs for solar
systems have changed dramatically in the
past five years. For example, houses in NSW
that installed solar in 2009 were paid 66
cents for every unit of electricity their solar
system generated. Today, houses that install
solar are paid only eight cents.
s
Electricity tariffs are becoming much
more complicated.
Households and small businesses used
to pay the same amount for electricity no
matter when they used it. Today, ‘time of use’
electricity tariffs are commonplace, varying from
six cents in the middle of the night, to 50 cents
at peak time, usually about 6pm.
Some utilities are even introducing residential
‘demand’ tariffs. Customers pay a rate based
not only on the energy (kWh) they use, but also
on their maximum power demand (kW) during
the billing period.
What will drive the mass uptake of battery
systems is simple economics.
Yet no one really expects the mass
uptake of batteries to mean that customers
will become truly independent of the grid.
The electricity grid is a really useful way of
distributing energy to where it is needed.
Being completely independent of the grid
would mean many more batteries and solar
panels than is economic. Only old guys in
Land Rovers are likely to become entirely
self-sufficient.
Batteries will be installed in houses and
businesses that remain grid-connected.
The battery is simply a way of reducing a
customer’s electricity costs.
Having considered these changes in the
industry, investment bank Morgan Stanley
predicts that about 2.4 million Australian