Short answer
From May–December 2026, the federal factor is 6.8 STCs per eligible kWh. The first 14 kWh receives 100% of that factor, 14–28 kWh receives 60%, and 28–50 kWh receives 15%.
Estimated 2026 battery rebate by usable capacity
The dollar value varies because installers sell certificates at different prices and may deduct administration. This table shows a transparent $35–$40 value per certificate.
| Usable capacity | Estimated STCs | Support at $35 | Support at $40 |
|---|---|---|---|
| 5 kWh | 34 | $1,190 | $1,360 |
| 10 kWh | 68 | $2,380 | $2,720 |
| 13.5 kWh | 91 | $3,185 | $3,640 |
| 20 kWh | 119 | $4,165 | $4,760 |
| 28 kWh | 152 | $5,320 | $6,080 |
| 40 kWh | 164 | $5,740 | $6,560 |
| 50 kWh | 174 | $6,090 | $6,960 |
The official clearing-house price is $40 per certificate excluding GST, but the amount credited on a retail quote may be lower.
How the May 2026 formula works
STCs = floor(weighted usable kWh × 6.8)Weighted capacity = first 14 kWh + 60% of the next 14 kWh + 15% of the next 22 kWh.For a 40 kWh battery, the regulator’s worked example produces 164 certificates: 95 from the first tier, 57 from the second and 12 from the third.
Basic eligibility checks
- The battery’s nominal capacity must be at least 5 kWh and no more than 100 kWh.
- Certificates are only calculated on the first 50 kWh of usable capacity.
- The installed battery and inverter must be on the approved product lists.
- The installation must be completed by an appropriately accredited installer and paired with solar.
- Only one battery installation at a premises can receive the incentive.
Primary sourceClean Energy Regulator — Solar batteries ↗Current factor, taper, capacity rules and eligibility.
Rebate checked. Now check the quote.