This is the year-specific view of commercial solar incentives. For the structure, see commercial solar rebate in Australia. Here the focus is what 2026 looks like, and what is coming.
The 2026 numbers
For installs in 2026, the deeming period is five years. The zone ratings are 1.622, 1.536, 1.382 and 1.185. At the time of writing the STC market has been roughly $38 to $40, with the clearing house ceiling at $40. LGCs, for systems above 1 MW and older systems above 100 kW, have been roughly $6 to $9 in September 2026. Solar above 100 kW and up to 1 MW installed from 1 October 2026 creates STCs instead, with a fixed five-year deeming period; see mid-scale solar STCs.
| System | Zone 3 STCs (2026) | At $38 to $40 |
|---|---|---|
| 30 kW | 207 | $7,866 to $8,280 |
| 60 kW | 414 | $15,732 to $16,560 |
| 99 kW | 684 | $25,992 to $27,360 |
What changes in January
On 1 January 2027 the small-scale deeming period (up to 100 kW) falls to four years, cutting the STC count by 20 per cent for the same system. A 60 kW system in zone 3 falls from 414 to 331. On a commercial job, that difference runs to several thousand dollars. See what changes in January and is the STC scheme ending.
Timing traps
- Install date, not contract date. The year of installation sets the deeming period.
- Grid approval delays. Network connection can slip a project over the new year.
- Registry timing. Claims should be lodged promptly after installation.
State support
States and territories may offer commercial incentives, finance or certificate schemes. These change, and caps and criteria vary. Check your state energy agency’s official page before relying on them.
From the desk: if your project is within a few weeks of year end, ask the installer to confirm in writing what happens to the discount if the install date moves.
Combining with other support
Some businesses can combine STCs with state-based incentives or finance. Rules on stacking differ by program, and some programs require approval before work starts. Check the scheme’s official page before you sign a contract, not after, because retrospective applications are often refused.
What this means for you
Plan the project so the installation and any grid sign-off fall comfortably before 31 December if you want the five-year figure. For the installer side, see STC trading, pricing and the resources hub.