floor(6.8 × tiered usable kWh) × $39.65
- 100% of the first 14 usable kWh counts
- 60% of capacity from 14 to 28 kWh
- 15% of capacity from 28 to 50 kWh, nothing above
13.5 kWh usable → 91 STCs
$3,608
Every battery size and the step-down dates → Solar battery rebate calculator
The federal battery rebate calculator, with every state program for your postcode stacked and sourced. A 13.5 kWh battery currently earns about $3,608 federally (at the 15 October 2026 price of $39.65 per STC), and that rate drops on 1 January 2027. Type a postcode and the answer appears straight away, no email needed.
Rebates are set by state + network
$500/quarter
≈ $2,000 a year
Your place
Type your postcode and your number appears here. Federal battery discount, solar STCs, state extras, all stacked, all sourced. Nothing gated.
Next step-down 1 January 2027: the factor falls from 6.8 to 5.7 STCs per usable kWh, so the same 13.5 kWh battery earns $3,013 instead of $3,608, $595 less.
Federal battery discount · Solar STCs · State programs · Every figure sourced and dated
Pricing new panels rather than just the battery? Try the solar cost calculator for the installed price after STCs and payback.
01 · The formulas
How this calculator works
No black box. These are the two federal formulas the calculator runs, straight from the legislation, plus the state programs it stacks on top.
floor(kW × zone rating × 5) × $39.65
- 5 deeming years for a 2026 install, drops by one every 1 January
- Zone rating set by your postcode, see the table below
- Scheme ends 31 December 2030
6.6 kW in Sydney → 45 STCs $1,784
Check any postcode in the STC calculator → The four STC zones (solar)
| Zone | Rating | Example cities | 6.6 kW rebate |
|---|---|---|---|
| Zone 1 | 1.622 | Remote inland NT, QLD, SA and north-west WA (no capital cities) | $2,101 |
| Zone 2 | 1.536 | Darwin | $1,983 |
| Zone 3 | 1.382 | Sydney, Brisbane, Adelaide, Perth, Canberra | $1,784 |
| Zone 4 | 1.185 | Melbourne, Hobart | $1,546 |
Your zone is set by your postcode, not your state: the NT spans zones 1, 2 and 3. Full zone detail on the STC calculator.
What stacks on top, by state
- NSW VPP incentive, only if you join a VPP amount varies by provider NSW rebates →
- VIC Solar Homes panel rebate (solar only, income under $150,000) up to $1,400 VIC rebates →
- WA Residential Battery Scheme, $130/kWh (Synergy), VPP required capped at $1,300 WA rebates →
- SA REPS VPP incentive concession and hardship households only SA rebates →
- ACT Sustainable Household Scheme loan (not a rebate) 3% up to $20,000 ACT rebates →
Everywhere else the federal programs still apply in full. State detail lives on the solar rebates by state page.
02 · Quote check
Check your quote against the current rates
Every row computed from the current 6.8 STCs/kWh factor and the $39.65 spot price. If your quote's battery discount is far off these numbers, ask why.
| Battery (usable) | STCs | Gross at the $40 cap | Typical net on invoice |
|---|---|---|---|
| 10 kWh | 68 | $2,720 | $2,440-$2,520 |
| 13.5 kWh | 91 | $3,640 | $3,294-$3,402 |
| 16 kWh | 103 | $4,120 | $3,709-$3,830 |
| 20 kWh | 119 | $4,760 | $4,294-$4,435 |
| 27 kWh | 148 | $5,920 | $5,319-$5,494 |
Net assumes the typical installer pass-through of $244-$252 per counted kWh after admin fees. Program detail on the solar battery rebate page.
03 · The step-down schedule
The battery factor is on a published clock
Set by the Clean Energy Regulator, not a sales tactic. Here is every scheduled step-down and what each one does to the rebate on a 13.5 kWh battery, by installation date.
| Installation period | Factor (STCs/kWh) | Rebate on 13.5 kWh |
|---|---|---|
| 1 Jan 2026 to 30 Apr 2026 | 8.4 | $4,480 |
| 1 May 2026 to 31 Dec 2026 now | 6.8 | $3,608 |
| 1 Jan 2027 to 30 Jun 2027 | 5.7 | $3,013 |
| 1 Jul 2027 to 31 Dec 2027 | 5.2 | $2,776 |
| 1 Jan 2028 to 30 Jun 2028 | 4.6 | $2,458 |
| 1 Jul 2028 to 31 Dec 2028 | 4.1 | $2,181 |
| 1 Jan 2029 to 30 Jun 2029 | 3.6 | $1,903 |
| 1 Jul 2029 to 31 Dec 2029 | 3.1 | $1,626 |
| 1 Jan 2030 to 30 Jun 2030 | 2.6 | $1,388 |
| 1 Jul 2030 to 31 Dec 2030 | 2.1 | $1,110 |
Source: Clean Energy Regulator, Solar batteries. Checked 19 October 2026; dollar figures at the 15 October 2026 price of $39.65 per STC.
04 · Common questions
Battery rebate questions, answered with the formula
How do I calculate the federal battery rebate?
STCs earned × the STC price. A battery earns 6.8 STCs per usable kWh, with capacity counted at 100% for the first 14 kWh, 60% from 14 to 28 kWh and 15% from 28 to 50 kWh, then rounded down to a whole certificate. At the current $39.65 spot price, a 13.5 kWh battery earns 91 STCs, about $3,608 gross before installer admin fees.
What is the rebate for a 10 kWh battery?
A 10 kWh (usable) battery earns 68 STCs: 6.8 × 10, rounded down. At the current $39.65 spot price that is about $2,696 gross. After typical installer admin fees, expect a net discount of roughly $2,440 to $2,520 on the invoice, plus any state incentive that stacks on top.
Does the calculator include state rebates?
Yes. It stacks the federal battery discount and solar STCs with the live state programs for your postcode: the WA Residential Battery Scheme ($130 per usable kWh, capped at $1,300 for Synergy customers) and Victoria's Solar Homes panel rebate (up to $1,400, income-tested). For NSW it shows the VPP incentive as an "up to" line: it only applies if you join a VPP, and NSW publishes no fixed amount, so treat it as an upper estimate. SA's REPS incentive is flagged as concession households only. Closed programs are excluded.
Why is my installer's number different?
Usually one of three reasons. Gross versus net: we show the gross STC value at the $39.65 spot price, while installers pass through a net figure after admin fees, typically $244 to $252 per kWh on the first 14 kWh. Usable versus nominal capacity: a "13.5 kWh" battery is rebated on its usable capacity, which can be lower than the nameplate number. Or the quote was priced on an old factor or a stale STC price. If the gap is more than about 10%, ask the installer to show the STC line item and the date it was calculated.
How much is the battery rebate in my state?
The federal part is the same everywhere: about $3,608 on a 13.5 kWh battery, at the 15 October 2026 price of $39.65 per STC. WA adds $130 per usable kWh capped at $1,300 for Synergy customers, for $4,908 in total. NSW adds a one-off incentive only if you connect the battery to a virtual power plant; NSW publishes no fixed amount (it scales with the capacity you make available, up to 28 kWh, and varies by provider). SA's REPS incentive is limited to concession and hardship households, the ACT lends at 3% rather than discounting, and VIC, QLD, TAS and NT have no battery rebate. Each state calculator has the full working.
How much does the battery rebate drop?
On 1 January 2027, when the battery factor steps down from 6.8 to 5.7 STCs per kWh. On a 13.5 kWh battery that is $595 less rebate for exactly the same install. The Clean Energy Regulator's schedule keeps stepping down every 1 January and 1 July until the program ends in December 2030, applied by installation date. The solar STC deeming period also drops by one year every 1 January.