For three Brisbane summers, the sun has helped cool Sandra Englart's home.
Solar panels power the retiree's air conditioner during the day and generate more electricity than she uses.
But a household battery to store that unused energy was out of Ms Englart's budget.
"It was quite expensive really, and we couldn't see that it was an economically viable proposition at the time," she said.
This year the federal government will begin rolling out 400 community batteries to store excess energy produced by households like Ms Englart's.
Climate Change and Energy Minister Chris Bowen said the program would allow Australians with rooftop solar to reap the benefits of storage without the cost of a household battery.
"Once the community battery is up and running, then households will be able to apply to participate to store their renewable energy," he said.
Mr Bowen said people would have to pay a "small administrative cost" to use the batteries.
"We're in most cases talking a couple of dollars a week. But certainly, the benefits of the reduced bills from being able to store renewable energy will far outweigh that cost," he said.
The government is offering grants of $100,000 to $500,000 for groups to install and run the batteries.
"It'll be in most cases an electricity distributor, or an electricity distributor in partnership with a community group," Mr Bowen said.
Bids for the first 58 batteries open at the end of the month.
Which communities are getting batteries?
Of the first tranche, 13 batteries will be installed in Queensland, 15 in New South Wales, 15 in Victoria, three in the Australian Capital Territory, two in South Australia, two in Tasmania and six in Western Australia.
The first round includes batteries promised during last year's federal election campaign.
Projects are expected to begin in June and must be finished by 31 March, 2025, according to grant guidelines.
"We'll have batteries up and running this calendar year," Mr Bowen said.
Lachlan Blackhall, who heads the Australian National University's Battery Storage and Grid Integration Program, said those unable to install solar panels, such as renters and apartment owners, also benefited from community batteries.
Mr Blackhall said having storage close to generation made the energy network more efficient.
"That puts downward pressure on electricity prices for everybody," Mr Blackhall said.
Taking pressure off the grid
Australia has the highest uptake of rooftop solar in the world, according to the Department of Climate Change, Energy, the Environment and Water (DCCEEW).
More than three million homes, or 30 per cent of Australian households, produce their own electricity with solar panels, DCCEEW's website said.
But that has created challenges for grid stability.
"We have lots of energy in the system at lunchtime, and we have not enough energy in the system at night necessarily," Mr Bowen said.
New South Wales electricity distributor Ausgrid is trialling community batteries in neighbourhoods with a high concentration of solar panels.
"[The batteries are] designed to solve local issues such as network constraints, over voltage associated with too much solar, and also contribute to the market response to decarbonisation," Rob Amphett Lewis, Ausgrid's Chief Customer Officer, said.
He said the company would previously have dealt with an abundance of generation by increasing the size of wires and transformers.
"When you have significant amounts of solar, maybe 50 per cent of the local community having solar, then that's when these sorts of issues can really crop up. And when this sort of solution really makes a lot of sense," Mr Amphett Lewis said.
Ausgrid is trialling batteries in the Sydney suburbs of Bankstown and Beacon Hill, as well as in the city of Newcastle, north of Sydney.
The company said households connected to the battery can store up to 10 kilowatt hours of electricity a day. A measurement device records how much excess energy a participant has stored, and credits are applied against their energy usage that day.
Ausgrid estimates most participants would receive between $50 and $250 a year in credits.
Mr Blackhall said community batteries allowed networks to get more capacity out of existing poles and wires.
"This ultimately reduces the amount of investment we're going to have to make in electricity networks over time, which ultimately provides downward pressure on electricity prices for everybody," Mr Blackhall said.
In the Sunshine State, government-owned company Energy Queensland is rolling out at least a dozen "community-scale" batteries.
One at Bohle Plains, on the outskirts of Townsville, is capable of powering 4,000 homes for about an hour.
It was built in 2020 to "soak up" excess renewable energy, take pressure off substations, and "help out" during demand peaks.
The company said it would inform decisions on network infrastructure spending that may help push electricity prices down.
The Victorian government has its own grant program to spark the uptake of community batteries.
Last year, the state's first inner urban battery was installed in the Melbourne suburb of North Fitzroy.
It redistributes excess solar energy to local homes, regardless of whether they have solar panels.
Mr Blackhall said the federal government's scheme would kickstart the uptake of community batteries.
"We will of course need significantly more batteries to be installed in our electricity system over the coming decades," he said.
"Through this program there are very important lessons to be learned around how we operate community batteries for the benefit of householders and the community.
"Rather than the energy transition being a challenge, we should think of simply needing a new energy operating paradigm for the 21st century electricity system that is going to support our energy transition and allow us to decarbonise our economy."
