Australia's solar rebate works through the Small-scale Renewable Energy Scheme, which issues small-scale technology certificates, or STCs, based on a system's size, its location, and how many years remain until the scheme's legislated end in 2030. Installers claim these certificates on the homeowner's behalf and build the value straight into the quoted price, which is why Australian solar quotes already look discounted before you sign anything.
The short version
- The solar rebate works through STCs, a certificate scheme, not a cash payment, and installers usually claim it for you as an upfront discount.
- STCs are calculated from your postcode's solar zone rating, the years remaining to the scheme's 2030 end date, and your system size.
- The deeming period for 2026 is 5 years, and it drops by one every January, so the discount shrinks a little every year.
- An STC is worth roughly $37 to $39 on the open market in 2026, with a government guaranteed ceiling of $40.
- The federal battery rebate, live since 1 July 2025, uses the same STC mechanism with its own capacity based rate table.
Deeming period countdown to the scheme's 2030 end
- 2026: 5 years remaining. Current level.
- 2027: 4 years remaining. About 20 percent lower yield than 2026.
- 2028: 3 years remaining. About 40 percent lower yield than 2026.
- 2029: 2 years remaining. About 60 percent lower yield than 2026.
- 2030: 1 year remaining. About 80 percent lower yield than 2026, scheme ends 31 December 2030.
The formula behind the discount
STCs are calculated as postcode zone rating, multiplied by the deeming period in years, multiplied by system size in kW. Australia is split into four solar zones based on average irradiance, each with its own fixed multiplier, roughly 1.622 for the sunniest zone down to about 1.185 for the least sunny (broadly Tasmania and parts of Melbourne). The deeming period is simply the number of years left until the scheme ends on 31 December 2030, so it counts down by exactly one every January. For calendar year 2026 that period is 5 years.
Why the rebate quietly shrinks every year
Because the deeming period is the main variable that changes over time, the same solar system in the same postcode generates fewer STCs, and therefore a smaller discount, each year, purely from the countdown to 2030. This has nothing to do with panel prices or installer margins, it is a built in feature of the scheme, and it is one reason installed solar prices have crept upward even as hardware costs fall.
How the point of sale discount actually works
You do not create and sell your own STCs in the normal buying process. Instead, you sign over your right to claim them to a registered agent, almost always your installer, in exchange for an upfront reduction in your invoice. The installer then sells those certificates into the STC market. A small number of homeowners choose to register and sell the certificates themselves through the REC Registry, but this is slower and rarely worth the hassle compared to the instant discount most installers already build into their quotes.
What an STC is actually worth
The Clean Energy Regulator runs a Clearing House that guarantees a fixed ceiling price of $40 per certificate excluding GST. In practice, most STCs trade on the open market a little below that, typically $37 to $39 through 2026. That price floats daily with supply and demand, so it is not a locked in government rate, it is closer to a commodity price with a government imposed ceiling.
Does the battery rebate work the same way
Yes, with its own rate table. Since 1 July 2025 the Cheaper Home Batteries Program has used the same STC mechanism for batteries installed alongside solar, calculated on usable capacity in kWh rather than the zone and deeming formula used for panels. That rate has already changed twice in 2026, and is covered in full in our battery rebate guide.
What happens after 2030
The Small-scale Renewable Energy Scheme is legislated to end on 31 December 2030, at which point the STC mechanism stops entirely for new installs. There is no confirmed replacement scheme yet. In practical terms this means the earlier you install relative to that date, the larger your discount, since the deeming period, and therefore the STC yield, only ever goes down from here, never up.
What this means if you are comparing quotes
Ask whether the quoted price already reflects the STC discount, since almost every legitimate Australian solar quote does. Be wary of a quote that lists a much larger "rebate" as a separate deduction on top of an already low headline price, since that can be a sign the STC value has been double counted or inflated to make the deal look better than it is.
See real installed prices in our solar cost guide, and check the battery specific rate in our Cheaper Home Batteries rebate guide. Compare installers on the WattsUp directory.
Frequently asked questions
What is an STC?
A small-scale technology certificate, the unit used to calculate Australia's solar and home battery rebates. Installers typically claim these on your behalf and pass the value back as an upfront discount on your invoice.
How is the STC rebate calculated for solar panels?
Postcode solar zone rating, multiplied by the deeming period in years remaining until the scheme ends in 2030, multiplied by system size in kW. For 2026 the deeming period is 5 years.
Do I get a cheque for the solar rebate?
No. In almost all cases the installer claims the STCs and reduces your quoted price by their value. You could sell the certificates yourself through the REC Registry, but almost no one does because it is slower than the standard point of sale discount.
Why does the solar rebate get smaller every year?
Because the deeming period, one of the numbers in the STC formula, counts down by one year every January on the way to the scheme's legislated end on 31 December 2030. A smaller deeming period means fewer certificates for the same system.
How much is an STC worth right now?
Around $37 to $39 on the open market through 2026, with a government guaranteed ceiling of $40 through the Clean Energy Regulator's Clearing House. The exact price floats with supply and demand.