The tiny island off the southeast coast of Tasmania is home to a solar battery trial.
The idea is that solar batteries could help the islanders save money on their power bills, and the energy stored in their batteries could help shore up the energy network, especially during the tourist season.
Local John Kobylec was hesitant to invest in solar energy before the trial — which subsidises the full cost of the battery — began two years ago. Now he is a convert.
“We definitely got a lot more saving on our power bill,” said Mr Kobylec, one of 33 households participating in the trial so far.
“But the good part of it really, is they’re using the power that’s been stored in our batteries to help the community of Bruny Island with their electricity.”
“That saves the cost of having to fire up the diesel generators on Bruny which they had to do a lot because of the extra visitors we get here all the time.”
This so-called virtual power plant will be commonplace in the future, predicts Evan Franklin, a University of Tasmania researcher working on the Federal government funded trial along with the state energy operator TasNetworks.
“I think that in another 10, 20 years’ time, there’s going to be 1 or 2 million batteries installed in households behind the meter, and they can together tackle [the issue of network supply],” he said.
So, is it time to invest in a solar battery system or upgrade your existing system to tap into the trend?
“The answer is it’s a little bit complicated,” Dr Franklin said.
You’re probably familiar with solar panels. These collect solar energy that’s converted into electricity via the inverter — the box on the wall. Any excess not used by the household is sent to the grid in return for a discount on your power bill — a feed-in tariff.
Simple solar panel systems do not have batteries. But you can also buy hybrid systems that have batteries or are battery ready.
The batteries store energy for you to use at a later time or to be sent back into the grid at a time that capitalises on energy prices.
Batteries can also allow you to go off-grid or provide an alternative to joining the grid.
There are different kinds of battery technologies, which have different pros and cons in terms of efficiency, but the main one currently dominating the market is lithium ion, said industry analyst Warwick Johnston.
“We’re starting to see a shift in recognising that the battery is not just a chemistry, it’s what you do with it as well,” said Mr Johnston, who is the head of solar consultancy firm SunWiz.
“Some providers differentiate themselves on what they’re able to achieve with home energy control.”
“At the moment every inverter that’s installed in the country has the ability to autonomously operate to detect what’s going on locally and respond as requested and programmed,” said Mr Johnston who also sits on the Clean Energy Council (CEC).
“But then we’re looking at the new ‘smart’ batteries having communications with the network operators to respond in a dynamic way.”
The solar industry is booming, with a record number of people putting solar photovoltaics on their rooftops in 2017.
“We have the right conditions. High electricity prices, lots of sunshine, strong familiarity with solar technology and higher uptake of new technologies in general,” Mr Johnston said.
Now, attention is turning to solar batteries. The CEC reports about 12 per cent of new solar systems installed in 2017 included batteries, and that installations of solar batteries tripled from 6,750 in 2016 to more than 20,000 in 2017.
“This year it looks like we are on target to install 33,000,” Mr Johnston said.
While some people are investing in smaller batteries, Mr Johnston said most people commonly pay between $10,000 and $15,000 for a “decent sized” battery.
The main thing driving this rise according to a survey of members of consumer group CHOICE, is the desire to be independent of electricity companies.
“Most people realise that practically they still need to keep a connection but they’d like to be as independent of it as they can be,” said Chris Barnes, CHOICE’s household product testing and content team leader.
Plus there are the environmental considerations.
“Some people think it’s a greener way of living, all that sort of thing, but actually that’s not as much of a motivator as you might think,” Mr Barnes said.
“For most people it does come down to dollars and cents and trying to reduce their bills.”
Whether or not solar batteries make economic sense is an exercise in cost vs benefit.
“The way this is usually measured is ‘will the system — the panels, the inverter, the battery altogether — will it pay for itself before its product warranty expires?'” Mr Barnes said.
According to the CEC, the cost of lithium ion batteries has fallen by 80 per cent since 2010 and is expected to halve again within seven years.
“As battery prices come down they’ll become more attractive,” said Niraj Lal, a visiting fellow at the Australian National University’s Centre for Sustainable Energy Systems.
“They’ll also have the ability to provide some of these additional network services to aggregate and bid into the wholesale market or take part in a virtual power plant.”
But for now solar researchers, industry analysts and consumer groups all agree: unlike solar panels, it doesn’t quite make economic sense for the average householder to invest in batteries.
“That’s longer than the warranty for the battery system, so we’re not really there yet.”
Mr Barnes agreed.
“If I was to answer absolutely I’d advise most people to hold off,” he said.
In saying that however, all agreed there are situations where the decision may pay off.
Weighing up the equation comes down to your own individual circumstances — there is no rule of thumb.
“There are definitely people who will make it work for themselves economically if they’re in the right location, if they’re using their power in a certain way, if they’ve got particular incentives they can make use of,” Mr Barnes said.
To work out whether or not investing in batteries will pay off for you, there’s a few things to consider, such as:
“If you consume more energy then you’ll have a quicker payback with a solar storage system than if you’re only consuming a little bit of energy,” Mr Johnston said.
“If most of your energy is consumed at night then you’ll have more favourable outcomes from installing batteries than not,” Mr Johnston said.
This not only affects the amount of sunshine you get but also the electricity prices and other factors such as feed-in tariffs — the amount you are paid to contribute energy to the grid.
“If you live in South Australia, a combination of high solar, and high electricity prices means that solar on its own is an amazingly high payback, but even when you add a battery you can get payback in under five years,” Mr Johnston said.
But it may not be worthwhile in areas such as the Northern Territory which has generous feed-in tariffs.
“Feed-in tariffs have dwindled quite a bit except in the NT where the feed-in tariff you get paid is the same as you would pay as buying that same power out of the grid in the first place,” Mr Barnes said.
Some state and local governments also offer battery subsidies.
If you’re prepared to venture into solar batteries for economic, emotional or environmental reasons, or you just want to be an early adopter, Mr Barnes offers the following tips.
The general consensus within the industry is that the tipping point on price will happen within two to five years.
Even if batteries don’t make economic sense for most people just yet, investing in solar panels does.
“Now is still a fantastic time to get a solar panel system, and you can always add batteries to a solar panel system easily at a later stage,” Mr Johnston said.
“The reason for that is the standards are evolving and by the time that people get around to doing installations, the standards will have changed.”
There are still a few issues with sending stored energy to the network without flooding it all at once to be ironed out too, according to Dr Franklin.
“Networks know about it and there hasn’t really been a good solution to date, which is to make sure they operate in a coordinated fashion,” said Dr Franklin.
Dr Franklin is developing software using algorithms along with researchers from ANU and the University of Sydney to coordinate output from households to the Tasmanian network.
“It needs to be a really clever virtual power plant to actually work on electricity networks.”
Back on Bruny Island, Mr Kobylec has become the go-to person for other islanders curious about the trial.
“They are not installing batteries at this stage because [batteries] are more expensive, but they are looking at the market, and seeing when the price of the batteries comes down,” Mr Kobylec said.
“You have to make up your own decision as to your return and your own household use as to whether you also install a battery. But to me it operates really fantastically and makes sense.
“I think this is definitely the way of the future.”
Energy Stuff helps provide battery solutions to residential solar systems. Call us for further information 1300 656 205 or go to our website at https://ongrid.energystuff.com.au/solar-system-battery-storage/