Solar Rebate Calculator

How Much Is Your Solar Rebate Worth?

The Australian government's STC rebate reduces the upfront cost of solar. It's being phased out by 2031, so the sooner you install, the more you save.

Average home, 2-3 people · ~30m2 of roof space

Deeming period: 5 years remaining. The rebate decreases every January 1st until it reaches zero in 2031.

How the Solar Rebate Works

What is the STC rebate?

The Small-scale Technology Certificate (STC) scheme is the Australian government's way of making solar more affordable. When you install solar panels, your system generates STCs based on how much renewable energy it will produce over its remaining lifetime in the scheme. These certificates have real monetary value because energy companies are legally required to buy them.

In practice, your installer handles everything. They create and sell the STCs on your behalf, then deduct the value as an upfront discount on your system price. You don't need to register, trade, or claim anything yourself.

How are STCs calculated?

The formula is straightforward:

System Size (kW) x Zone Rating x Deeming Period = Number of STCs
  • System Size:The total kilowatt capacity of your solar panels. Bigger systems generate more STCs.
  • Zone Rating:Australia is divided into 4 zones based on sunlight. Zone 1 (1.622) gets the most sun, Zone 4 (1.185) gets the least. Sydney is Zone 3 (1.382).
  • Deeming Period:The number of years remaining until the scheme ends in 2031. In 2026, that's 5 years. Each January 1st, this drops by one.

The 4 STC Zones

Zone 1 (Rating: 1.622)

Darwin, Far North QLD, Central Australia. Highest rebate.

Zone 2 (Rating: 1.536)

Brisbane, Perth, most of QLD and WA.

Zone 3 (Rating: 1.382)

Sydney, Melbourne, Adelaide, ACT. Most of the population lives here.

Zone 4 (Rating: 1.185)

Tasmania, southern Victoria. Lowest rebate, still significant.

Why the rebate is decreasing

The STC scheme is designed to phase out by 2031. Every January 1st, the deeming period drops by one year, which means fewer STCs are generated and the rebate gets smaller. A 6.6kW system in Sydney that generated $2,052 in rebates in 2025 will only generate $1,710 in 2026, and $342 by 2030.

This isn't a sales tactic. It's how the legislation works. The federal government set up the scheme to encourage early adoption, and the incentive reduces every year by design.

What about the federal battery rebate?

Since 2024, the Cheaper Home Batteries Program also offers STC-style rebates for battery storage systems. Batteries with a minimum capacity of 5kWh are eligible. In 2026, batteries receive approximately 8.4 STCs per kWh of capacity. A 10kWh battery could save you around $3,192 on top of your solar panel rebate.

Current STC price

STCs trade on an open market, similar to shares. As of March 2026, the STC spot price sits at approximately $39.65 per certificate, near the $40 statutory clearing house cap. The price has been relatively stable in the $39 to $40 range throughout recent quarters, supported by steady purchasing activity from energy retailers. The historic low was $16, but the market has remained elevated due to strong demand. Your installer locks in the STC price at the time of installation.

Important note

The figures on this page are estimates based on current STC market prices and average system costs. Your actual rebate and system cost will depend on the specific panels, inverter, and installer you choose. For an exact figure, get personalised quotes from accredited installers.

Get 3 Free Solar Quotes

Free, no obligation. CEC-accredited installers only.