How a battery saves money
Without a battery, midday solar you do not use is exported for a feed-in tariff of a few cents. With a battery, that power is stored and used after sunset, replacing power you would buy at your full usage rate. The saving per kWh is the gap between the two, less round-trip losses of around 10%.
Yearly saving ≈ kWh stored each day × 365 × (usage rate × 0.9 − feed-in tariff)
Battery payback by capital city
| City | Usage rate | Feed-in | Saving a year | Payback |
|---|---|---|---|---|
| Adelaide | 41.91c | 2c | $913 | 9.1 years |
| Brisbane | 27.97c | 3c | $567 | 14.6 years |
| Canberra | 36.95c | 3c | $773 | 10.7 years |
| Darwin | 31.68c | 9.33c | $490 | 16.9 years |
| Hobart | 24.75c | 9.28c | $332 | 24.9 years |
| Melbourne | 31.98c | 1c | $710 | 11.7 years |
| Sydney | 33.14c | 3c | $685 | 12.1 years |
| Perth | 33.26c | 2c | $714 | 11.6 years |
Adelaide comes out best because South Australian usage rates are the highest. Hobart is worst: Tasmania's usage rate is the lowest of the capitals and its regulated feed-in tariff is high, so there is less to gain by storing solar instead of exporting it. Seven kWh a day is an average across the year; winter days give less spare solar.
What makes a battery worth it
Stronger case
Worth a look- High evening use and spare midday solar
- Time-of-use plan with expensive evening peaks
- A VPP that pays well, or the NSW VPP incentive
- WA rebate, especially for Horizon Power customers
- You value blackout backup
Weaker case
Think twice- Small solar system with little spare output
- Low evening use
- High feed-in tariff, as in Tasmania and the NT
- Planning to move house within a few years
Use your own numbers
Your smart meter data shows how much you export and how much you buy after dark. Put those into the battery payback calculator, and see what size battery you need.
Common questions
Sometimes. On flat-rate 2026-27 prices, a 10 kWh battery storing 7 kWh a day pays back in roughly 9 to 12 years in most capitals on our worked figures, and longer where usage rates are lower. Time-of-use pricing, VPP payments and state rebates shorten that.
It depends on the price, how much the battery cycles and the gap between your usage rate and feed-in tariff. Our worked example ranges from about 9 years in Adelaide to over 20 years in Hobart.
Only if you have the spare solar and evening use to fill it. A battery that rarely empties saves no more than a smaller one. The federal discount also tapers above 14 kWh.
Sources
Battery prices are from the Solar Choice Battery Price Index. Power prices are the 2026-27 regulated rates on our state pages, and feed-in rates come from regulators or the AER plan data. Last checked October 2026. Prices include GST unless we say otherwise.