6.6 kW × 1.382 (Zone 3) × 5 deeming years, floored = 45 STCs × $39.65 = $1,784
You don't claim this yourself. Your SAA-accredited installer creates the STCs and takes this value off your invoice as a point-of-sale discount, so the number above is what your quote should be cheaper by, not a cheque you receive afterwards. Cross-check it with the official REC Registry STC calculator.
Battery figures: Clean Energy Regulator data, to 1 July 2026; "1 in 17" is derived from it.
Only want the panels side? This is the federal solar rebate on its own. For every state program on top, see solar rebates by state; for a battery, the solar battery rebate. Want the whole installed price, not just the certificate value? The solar cost calculator runs this same STC formula against your system size and postcode, then adds the before/after price band, a battery add-on and an estimated payback.
What is the federal STC rebate?
STCs, Small-scale Technology Certificates, are a federal incentive legislated under the Renewable Energy (Electricity) Act 2000. Every accredited solar install earns certificates, and those certificates are tradable on a regulated market. In practice, your installer keeps the STCs in exchange for an upfront discount on your invoice, so you never claim anything; the rebate is baked into the quote.
It is the largest single solar discount available to Australian households, applies in every state and territory, and stacks with state programs like Victoria's Solar Homes rebate (up to $1,400). The scheme winds down on a fixed schedule: the "deeming period" in the formula drops by one year every 1 January until the rebate reaches zero for 2031 installs.
How the STC rebate is calculated (the honest formula)
STCs = floor(system kW × zone rating × deeming years)
rebate = STCs × STC price
As of 26 October 2026 (STC price checked against Demand Manager, STC spot market):
- System size: your panel capacity in kW (typical residential: 6.6 kW)
- Zone rating: 1.185 (Melbourne, Hobart) up to 1.622 (Zone 1, remote north-west). Table below.
- Deeming years: 5 for 2026 installs, dropping one year every 1 January until it hits zero in 2031
- STC price: spot price $39.65 on 15 October 2026 (Demand Manager, STC spot market); the clearing house caps it at $40 ex GST, and installer pass-through is typically $37-$40
- The floor matters: the certificate count is rounded down, never up
For a 6.6 kW system in Sydney (Zone 3, rating 1.382), installed in 2026:
floor(6.6 × 1.382 × 5) = 45 STCs × $39.65 = $1,784 off the invoice
Plenty of pages still quote $2,500 or more for a 6.6 kW system. Those figures come from the old 6-year deeming period, which ended on 31 December 2025. For 2026 installs the deeming period is 5 years, and a 6.6 kW Sydney system creates 45 STCs worth about $1,784 at today's $39.65 certificate price. If a quote or website shows a bigger federal rebate than that, it is running last year's numbers; check the date before you rely on it.
Are solar rebates being cut in 2026? The step-down, year by year
Yes, on a schedule. Every 1 January the deeming period drops by one year, and the rebate falls with it. Here is what a 6.6 kW system in Sydney (Zone 3) gets by install year, at today's $39.65 STC price:
| Install year | Deeming years | STCs (6.6 kW, Zone 3) | Rebate value |
|---|---|---|---|
| 2026Now | 5 | 45 | $1,784 |
| 2027 | 4 | 36 | $1,427 |
| 2028 | 3 | 27 | $1,071 |
| 2029 | 2 | 18 | $714 |
| 2030 | 1 | 9 | $357 |
| 2031 | 0 | 0 | $0 (scheme ended) |
Install a 6.6 kW system in Zone 3 this year and the federal rebate is $1,784; wait until January 2027 and it is $1,427, a permanent loss of $357. On a 10 kW system the gap is $555 ($2,736 this year vs $2,181 next). The rebate is set by the date the system is installed and registered, so December quotes need realistic install lead times.
STC zones: what each city gets in 2026
Australia is split into four STC zones by solar irradiance. Same system, different postcode, different rebate. Computed at the 15 October 2026 price of $39.65 per STC for 2026 installs:
| Zone | Rating | Example cities | 6.6 kW rebate | 10 kW rebate |
|---|---|---|---|---|
| Zone 1 | 1.622 | Remote inland NT, QLD, SA and north-west WA (no capital cities) | $2,101 | $3,212 |
| Zone 2 | 1.536 | Darwin | $1,983 | $3,013 |
| Zone 3 | 1.382 | Sydney, Brisbane, Adelaide, Perth, Canberra | $1,784 | $2,736 |
| Zone 4 | 1.185 | Melbourne, Hobart | $1,546 | $2,339 |
Zone ratings are set per postcode, not per state: the Clean Energy Regulator's table splits Australia into 137 postcode ranges, so an outer-metro or regional address routinely sits a zone away from its capital. Broken Hill (2880) is Zone 2 while Sydney is Zone 3; Mount Isa (4825) is Zone 2 while Brisbane is Zone 3; Alice Springs (0870) is Zone 1 while Darwin is Zone 2. The figures on this page, and on our city and state pages, are the capital's. The calculator above and the battery rebate calculator both read your own postcode's zone from that table instead.
Zone source: Clean Energy Regulator, Postcode zone ratings and zones for solar (photovoltaic) systems (as of 1 January 2020), made under the Renewable Energy (Electricity) (Zone Ratings and Zones for Solar (Photovoltaic) Systems) Instrument 2019. Checked against the published table on 22 September 2026.
How many STCs does your system create?
Bigger systems create more certificates, and the count is always rounded down. For 2026 installs in Zone 3 (Sydney, Brisbane, Adelaide, Perth, Canberra), at the 15 October 2026 price of $39.65 per STC:
| System size | STCs created (Zone 3) | Rebate value |
|---|---|---|
| 5 kW | 34 STCs | $1,348 |
| 6 kW | 41 STCs | $1,626 |
| 6.6 kW | 45 STCs | $1,784 |
| 8 kW | 55 STCs | $2,181 |
| 10 kW | 69 STCs | $2,736 |
| 13.2 kW | 91 STCs | $3,608 |
| 15 kW | 103 STCs | $4,084 |
| 20 kW | 138 STCs | $5,472 |
Considering a larger install? The 10 kW system page has the full generation, price and battery-pairing breakdown for that size.
What is the STC price in 2026?
STCs trade on an open market, so the dollar value of each certificate moves with supply and demand. The spot price was $39.65 on the latest trade we track (15 October 2026; Demand Manager, STC spot market), just under the $40 ex GST cap set by the Clean Energy Regulator's clearing house. Installer pass-through is typically $37-$40 per certificate. Because the market sits so close to the cap, most installers lock in a fixed STC value when they quote, so the discount you are shown is the discount you get even if the market dips slightly before your system is registered.
That price is exactly why the deeming-years step-down matters more than the STC price does: see how the deeming cut is calculated for the full working, and the solar payback period guide for what a smaller rebate does to your break-even point.
How to claim the STC rebate
You don't need to file anything yourself. The process is:
- Choose an SAA-accredited installer. (We match you with one for free.)
- Sign the install contract. The STC discount is shown as a line item.
- Installation. Usually completed in a single day.
- Within 1-2 weeks, the installer registers the system with the Clean Energy Regulator and creates the STCs.
- The installer keeps (or sells) the STCs and your invoice reflects the discount already.
That's it. The only paperwork you handle is the install contract itself. If your installer ever asks you to file STC paperwork yourself, that's a red flag: they're either not accredited or trying to charge full price and pocket the rebate.
STC rebate vs. state rebate vs. feed-in tariff
These three get confused all the time. Here's the difference:
| What it is | When you get it | Typical value |
|---|---|---|
| Federal STC rebate | Once, at point of sale (lower invoice) | $1,546-$1,983 on 6.6 kW in the capitals (2026) |
| State rebate (varies) | Once, at point of sale (where applicable) | Up to $1,400 solar (VIC, income-tested) · battery and VPP incentives elsewhere |
| Feed-in tariff | Ongoing, in cents per kWh exported | $200-$500/yr typical, see the NSW example |
Common questions
How to calculate the STC rebate?
Multiply three numbers and round down: STCs = floor(system size in kW × zone rating × deeming years). Zone rating runs from 1.185 (Melbourne, Hobart) to 1.622 (Zone 1, remote north-west); deeming years is 5 for a 2026 install and drops by one every 1 January. Multiply the STC count by the certificate price, $39.65 on 15/10/2026, to get the rebate. For 6.6 kW in Sydney (Zone 3) that is floor(6.6 × 1.382 × 5) = 45 STCs, worth about $1,784. The calculator above does this for your own system size, postcode and install year.
How much is an STC worth?
One STC is worth the market spot price, $39.65 on the latest trade we track (15 October 2026, Demand Manager, STC spot market), just under the $40 ex GST cap the Clean Energy Regulator's clearing house sets. Installer pass-through is typically $37-$40 per certificate, since most installers lock in a fixed value rather than pass on day-to-day market movement. A single certificate represents 1 MWh of eligible renewable generation, deemed upfront for the system's whole deeming period rather than metered year by year.
Are solar rebates being cut in 2026?
Yes, on a fixed schedule rather than by surprise. The federal STC rebate steps down every 1 January as the deeming period drops by one year: 5 for 2026, 4 for 2027, 3 for 2028, 2 for 2029, 1 for 2030, 0 for 2031. In dollars, a 6.6 kW system in Sydney gets about $1,784 for a 2026 install and about $1,427 from January 2027. The scheme is winding down as planned, not being scrapped early.
How much is the solar rebate on a 6.6 kW system?
For a 2026 install at the 15 October 2026 price of $39.65 per STC: about $1,546 in Melbourne and Hobart (Zone 4), $1,784 in Sydney, Brisbane, Adelaide, Perth and Canberra (Zone 3), and $1,983 in Darwin (Zone 2). The rebate is applied as a point-of-sale discount on your invoice, not paid to you in cash.
How do I calculate STCs?
STCs = system size (kW) × your zone rating × the deeming years, rounded DOWN to a whole certificate. Example for 6.6 kW in Sydney installed in 2026: 6.6 × 1.382 × 5 = 45.6, floored to 45 STCs. At the $39.65 market price that is about $1,784 off your invoice. Deeming is 5 years for 2026 installs and drops by one year every 1 January.
When does the solar rebate end?
31 December 2030 is the last day a new install earns STCs; from 2031 the rebate is zero. Before then it shrinks every 1 January as the deeming period drops: a 6.6 kW Sydney system gets about $1,784 in 2026, $1,427 in 2027, $1,071 in 2028, $714 in 2029, $357 in 2030.
Do I claim the STC rebate myself?
No. Your SAA-accredited installer creates the STC certificates and either keeps them in exchange for the upfront discount on your invoice, or sells them on the STC market and passes the proceeds to you as a discount. Either way, you never fill in a form; the rebate just lowers your invoice.
Is the STC rebate the same as a solar feed-in tariff?
No, they're different things. The STC rebate is a one-off upfront discount on your system. A feed-in tariff is the ongoing per-kWh credit your retailer pays for solar you export to the grid. You get both, but the STC discount is by far the bigger ticket item, and with feed-in tariffs now at a few cents per kWh in most states, it is the part worth timing correctly.