Add a battery to your existing solar
By Sithum Imarsha Last reviewed
A 10 kWh battery added to an average 2019 system in NSW pays back in about 10.2 years if it is installed between 1 May and 31 December 2026. On an average 2011 system in South Australia, the battery ends the 44c feed-in, which costs about $755 a year while it is paid (until 30 June 2028). Waiting until then costs you about $649 at these inputs, compared with installing it in October 2026.
Your result
Payback
10.2 years
$7,484 after the rebate, repaid from bill savings less any premium feed-in you give up.
- Federal rebate
- $2,516
- Extra inverter cost
- $1,000
- Saving a year
- $804
- Saving in year one
- $804
- Premium lost a year
- $0
- Premium lost in total
- $0
—
—
Or wait until the premium ends. It is paid No end date. Installed from —, the rebate is —. —
Fix the highlighted field to update.
How we calculated this
What your solar exports
Your bill figure, or our estimate: system kW × the CER deemed yield for your capital × the share a home exports with no battery. That share comes from Ausgrid 2012-13 data: about 45% for small systems, 81% at 6.6 kW and 86% at 10 kW.
7.62 kW → 23.8 kWh a day (our estimate from your system size)
What the battery can store
kWh out a day = the smaller of usable kWh × cycles and exports × round-trip efficiency.
8 kWh a day
Saving at the retailer feed-in rate
365 × (kWh out × import rate − kWh in × retailer feed-in rate).
$804 a year at 33.1c/kWh and 5c/kWh
The premium feed-in you give up
If the battery ends your premium, you lose it on every exported kWh until the premium would have ended. In SA the 44c is paid on top of the retailer rate on the first 45 kWh a day, so you lose 44c a kWh. In Queensland we assume the 44c replaces the retailer rate, so you lose the difference. If your distributor lets you keep it, there is no loss, but each stored kWh gives up the premium rate instead.
$0 a year, $0 in total
Cost of waiting until the premium ends
Only when the battery would end your premium now. Rebate lost (the rebate now − the rebate for the period after the premium ends) + the battery saving you miss until then − the premium you keep by waiting. Above zero, waiting costs you money. Below zero, waiting pays.
— + — − $0 = Not applicable
Payback
Cost after rebate = battery price + extra inverter cost − rebate. Then we add each year's saving (less battery wear each year, less the premium you give up while it would still be paid) until it covers the cost, up to 30 years.
$7,484 → 10.2 years
| Scheme | Rate | Ends | What a battery does |
|---|---|---|---|
| Queensland Solar Bonus Scheme (44c) | 44c | until its expiry date on 1 July 2028 | You lose it if a battery runs while the solar system on the 44c is operating, unless the battery has a separate connection to the network. Check with your distributor before adding a battery. |
| South Australia Solar Feed-in Scheme (44c) | 44c | until 30 June 2028 | You stop receiving the 44c distributor feed-in tariff if you install an energy storage device. |
| ACT renewable energy premium feed-in tariff | By connection year | for 20 years from connection | Paid on total generation for 20 years from connection. The Act has no battery clause, and we have not found an official answer on adding one. Ask Evoenergy. |
| Scheme | Ended | Source |
|---|---|---|
| Victoria Premium Feed-in Tariff | 1 November 2024 | energy.vic.gov.au (archived copy 7 May 2026) |
| NSW Solar Bonus Scheme | 31 December 2016 | NSW Resources and Energy (archived copy) |
| How it connects | Default | Range seen | Source |
|---|---|---|---|
| Battery-ready already | $0 | — | No extra inverter needed |
| AC-coupled inverter | $1,000 | $500 to $3,000 | WattMaths estimate inside the Solar Choice Battery Price Index (installer network average) spread (Aug 2025 to Aug 2026) and a $1,500 to $3,000 figure from a dated third-party page |
| Hybrid inverter swap | Your quote | — | No sourced figure: type your quote |
| Year | Average size |
|---|---|
| 2011 | 2.42 kW |
| 2013 | 3.95 kW |
| 2015 | 4.99 kW |
| 2017 | 6.40 kW |
| 2019 | 7.62 kW |
| 2021 | 8.46 kW |
| 2023 | 9.42 kW |
| 2024 | 9.89 kW |
| 2025 | 10.28 kW |
| 2026 | 10.16 kW |
Sources
- Queensland Government: Solar Bonus Scheme 44c
- Government of South Australia: Solar feed-in payments (archived)
- ACT Legislation Register: Electricity Feed-in (Renewable Energy Premium) Act 2008
- Victorian Government: Solar premium feed-in tariff (archived)
- Clean Energy Regulator: Solar batteries
- Clean Energy Regulator: Battery rebates are changing 1 May 2026
- DCCEEW: Cheaper Home Batteries Program
- DCCEEW: Small-scale technology certificates for batteries
- Canstar: electricity cost per kWh
- EnergyPlans: solar feed-in tariffs July 2026
- OTTER: Tasmanian feed-in tariffs
- WA legislation: Synergy A1 tariff, charges amendment by-laws 2026 (SL 2026/140)
- Clean Energy Regulator: Postcode zone ratings for solar panel systems
- Clean Energy Regulator: Small-scale installation postcode data
- Clean Energy Regulator: Quarterly Carbon Market Report, June quarter 2026
- AER: Electricity and gas consumption benchmarks for residential customers 2020
- Ausgrid: Solar home electricity data 2012-13 (archived copy)
- Synergy: average electricity bill by household type (read via the Wayback Machine, 2 April 2025)
- Solar Choice: Battery Price Index
- CSIRO: GenCost 2025-26 Final Report
Check your feed-in tariff first
Some older systems still earn a premium feed-in tariff. A battery can end it.
- South Australia 44c. For systems connected before 30 September 2011. Paid on the first 45 kWh exported a day, on top of the retailer rate, until 30 June 2028. It ends if you install any energy storage device.
- Queensland 44c. Paid until its expiry date on 1 July 2028. Not open to new customers. You lose it if a battery runs while the solar system on the 44c is operating, unless the battery has a separate connection. Check with your distributor first.
- ACT premium. Paid on total generation for 20 years from connection. We found no official answer on adding a battery. Ask Evoenergy.
When a battery ends a premium, you lose it on every exported kWh, not just the ones the battery stores. That can wipe out the saving for the years that are left. The calculator shows the loss, and the cost of waiting until the premium ends: the rebate you lose plus the battery saving you miss, less the premium you keep.
The inverter question
- Battery-ready or hybrid inverter: the battery plugs in. No extra inverter.
- AC-coupled battery: the battery brings its own inverter and works beside your solar inverter. Installer data put the extra cost at about $500 to $3,000.
- Swap to a hybrid inverter: replaces your solar inverter. We found no sourced figure, so type your quote. In Queensland a bigger inverter can also end the 44c.
Old systems make less
A 2011 system averaged about 2.4 kW. It makes too little to fill a large battery after the home’s daytime use. Type your daily export from your bill if you have it. It beats our estimate.
After the premium ends
Retailer feed-in rates are now a few cents a kWh. Once a premium ends, storing solar is worth far more than exporting it. That is when a battery pays back fastest.
Questions
I am on the SA 44c feed-in. Should I add a battery now?
South Australia ends the 44c distributor feed-in tariff when you install any energy storage device. It is paid until 30 June 2028, and only for systems connected before 30 September 2011. A battery now loses 44c on up to 45 exported kWh a day until then. Whether that outweighs the rebate you lose by waiting depends on how much you export. The calculator works out the cost of waiting until the premium ends.
Does a battery end the Queensland 44c?
It can. The Queensland Government says you lose it if you use batteries while the solar system on the 44c is operating, unless they have a separate connection to the network. It also says to check with your distributor before adding a battery. It is paid until its expiry date on 1 July 2028.
What about the ACT premium feed-in?
It is paid on total generation for 20 years from connection, from a gross meter. We found no official answer on adding a battery, so we leave it out of the maths. Ask Evoenergy before you commit.
Can I still get a premium feed-in in Victoria or NSW?
No. The Victorian Premium Feed-in Tariff ended on 1 November 2024. The NSW Solar Bonus Scheme closed on 31 December 2016.
Do I need a new inverter?
A battery-ready hybrid inverter needs nothing extra. Otherwise an AC-coupled battery brings its own inverter, or you swap your solar inverter for a hybrid. Ask for the same scope in every quote.
Does the rebate cover an existing battery?
Only new battery capacity counts. An older battery that already had program support does not.