Several questions come down to the same two numbers: 100 kWh and 50 kWh. One sets what is eligible. The other sets what earns.
The two ceilings
- 100 kWh nominal is the maximum size of an eligible battery system. A system between 5 kWh and 100 kWh nominal can be installed under the program, subject to the other rules.
- 50 kWh usable is the maximum capacity on which certificates are created. Capacity above 50 kWh earns no STCs.
Because certificates are capped, the discount stops growing at about 174 STCs at the 2026 factor of 6.8: roughly $6,600 to $7,000 at $38 to $40 per certificate, at the time of writing.
What 60 and 100 kWh earn
| Battery | Usable kWh counted | STCs (6.8) | Value at $38 to $40 |
|---|---|---|---|
| 50 kWh | 50 | 174 | $6,612 to $6,960 |
| 60 kWh | 50 | 174 | $6,612 to $6,960 |
| 100 kWh | 50 | 174 | $6,612 to $6,960 |
On a 100 kWh system the discount is a small share of the price. See 30, 40 and 50 kWh for the band below.
A battery over 50 kWh, commercial use
A business that installs 60 or 80 kWh gets the 50 kWh discount and no more. The program is aimed at households and small businesses with solar; see battery rebate for businesses. Larger commercial batteries may qualify for state incentives. One example is the NSW commercial battery incentive, reported to have started on 1 September 2026, so check the scheme’s official page for current terms. The Peak Demand Reduction Scheme and VPP revenue may also apply. See the VPP incentive stack.
A battery over 100 kWh
A system above 100 kWh nominal is not eligible for battery STCs under this program. It is a commercial-scale project, and the economics rely on network tariffs, demand charges and state schemes. The solar side is separate: the SRES now extends to solar of 100 kW to 1 MW installed from 1 October 2026, with a fixed five-year deeming period. See mid-scale solar STCs.
What this means for installers
For commercial jobs, split the claim cleanly: usable capacity from the CEC listing, a total that stays inside the 100 kWh nominal limit, and a calculation that is capped at 50 kWh. Over-claiming on capacity is a clear audit risk. See how STC audits work and the battery STCs pillar. For settlement terms see /pricing/ and /start-trading/.
What this means for you
Size the battery for your load and your tariff. The rebate stops rewarding capacity at 50 kWh, and mostly stops long before. See is a 30 or 40 kWh battery worth it.