The Australian Small-scale Technology Certificate (STC) rebate reduces the upfront cost of installing eligible solar PV systems by thousands of dollars. For 2025 and 2026, the rebate value continues its scheduled decrease on January 1st of each year as the scheme phases out toward its 2030 end date. While standard grid-connected solar systems easily qualify, off-grid and battery-only installations face stricter eligibility rules that buyers must navigate carefully to secure the discount.
What Are STCs and How Do They Work?
The Small-scale Renewable Energy Scheme (SRES) creates a financial incentive for individuals and small businesses to install eligible small-scale renewable energy systems. When you install an eligible solar photovoltaic (PV) system, wind turbine, or hydro system, it creates Small-scale Technology Certificates (STCs).
The number of STCs your system generates depends on three factors:
- System Size: The solar panel capacity in kilowatts (kW).
- Geographical Zone: Australia is divided into four solar zones based on how much renewable energy can be generated there. Zone 1 (e.g., Alice Springs) generates the most STCs, while Zone 4 (e.g., Melbourne) generates the least.
- Deeming Period: The number of years remaining until the scheme ends in 2030.
Instead of dealing with the complex STC market yourself, you typically assign the right to create your STCs to your registered solar installer. In exchange, the installer provides an upfront point-of-sale discount on your system.
Crucial Details for Off-Grid and Battery Buyers
Many general solar guides focus entirely on standard residential grid-tied systems. If you are building an off-grid cabin, adding a battery, or upgrading an existing system, there are specific nuances that dictate your eligibility:
- The January 1st Deeming Drop: The STC scheme is designed to phase out completely by December 31, 2030. Every year on January 1st, the "deeming period" drops by one year. This means a system installed in 2026 will generate fewer STCs (and thus a smaller discount) than the exact same system installed in 2025. The date of installation—not the date you signed the quote—determines the deeming period.
- Standalone Batteries Are Not Eligible: STCs are awarded for renewable energy generation, not storage. If you install a standalone home battery (like a Tesla Powerwall) without adding new solar panels, you will not receive any STCs for the battery itself.
- Off-Grid System Compliance: Off-grid solar PV arrays are eligible for STCs, but the installation must be completed by a Clean Energy Council (CEC) or Solar Accreditation Australia (SAA) accredited off-grid installer. The equipment (panels and inverters) must also be on the Clean Energy Regulator's approved list. DIY off-grid installations do not qualify for STCs.
- Market Price Fluctuations: The value of an STC fluctuates on the open market, typically trading between $35 and $40. While the Clean Energy Regulator has a clearing house price fixed at $40 (excluding GST), most STCs are traded on the open market for slightly less to ensure faster processing. Your installer absorbs this market risk when they offer you a fixed discount on your quote.
Illustrative Worked Example: 2025 vs. 2026 STC Discount
To understand how the phasing out of the scheme impacts your wallet, let's look at a realistic calculation for a standard 6.6kW solar PV system installed in Zone 3 (which includes Sydney, Brisbane, and Perth).
Note: This is an illustrative example. The exact STC market price varies, and installers may offer slightly different STC values based on their trading partners.
The STC Formula:
System Size (kW) × Zone Multiplier × Deeming Period (years) = Number of STCs
(The result is rounded down to the nearest whole number)
- Zone 3 Multiplier: 1.382
- Assumed STC Trade Price: $38 per certificate
Scenario A: Installed in 2025
- Deeming Period: 6 years (2025 through 2030)
- Calculation: 6.6 kW × 1.382 × 6 years = 54.72 (Rounds down to 54 STCs)
- Illustrative Discount: 54 STCs × $38 = $2,052
Scenario B: Installed in 2026
- Deeming Period: 5 years (2026 through 2030)
- Calculation: 6.6 kW × 1.382 × 5 years = 45.60 (Rounds down to 45 STCs)
- Illustrative Discount: 45 STCs × $38 = $1,710
By delaying the installation from 2025 to 2026, the upfront discount drops by approximately $342 for a 6.6kW system. For larger off-grid arrays (e.g., 15kW), the year-over-year drop is significantly larger.
Practical Checklist for Securing Your STC Discount
- Verify Installer Accreditation: Ensure your installer is accredited for the specific type of system you are building (grid-tied vs. standalone/off-grid).
- Check Approved Products: Confirm that your specific solar panels and inverters are on the Clean Energy Regulator's approved list.
- Review the Quote: The STC discount should be clearly itemized on your solar quote. It is usually listed as a point-of-sale discount rather than a post-installation rebate.
- Time Your Installation: If you are nearing the end of the calendar year, confirm with your installer that the system will be fully installed and commissioned before January 1st to lock in the current year's higher deeming period.
Frequently Asked Questions
Do I receive a cash payment or check in the mail for STCs?
No. While it is technically possible to create and trade STCs yourself through the REC Registry, the process is complex and time-consuming. In almost all residential and small commercial cases, the system owner assigns the STCs to the installer, who applies the value as an upfront discount on the invoice.
Are home battery storage systems eligible for STCs?
No, standalone batteries do not generate STCs because they store energy rather than generate it. However, if you install a new hybrid system (solar panels plus a battery simultaneously), the solar panels will generate STCs, reducing the overall package cost. Certain state-level rebates may offer separate incentives specifically for batteries.
Does upgrading an existing off-grid solar system qualify for new STCs?
Yes, but only for the new eligible generation capacity added. If you add 3kW of new solar panels to an existing off-grid system, you can claim STCs for that new 3kW array, provided the new equipment is on the approved list and installed by an accredited professional. You cannot claim STCs twice for the original panels.
What happens to the STC rebate after 2030?
The Small-scale Renewable Energy Scheme is legislated to end on December 31, 2030. After this date, the deeming period reaches zero, and no new STCs will be created for small-scale solar installations.
How does the January 1st deeming period drop affect my quote?
If you sign a quote in November but the installation is delayed until January, your system will be subject to the new year's lower deeming period. Most reputable installers include a clause in their contracts stating that the final price may be adjusted if the installation crosses into a new calendar year and the STC value drops.
