STC zones, explained
The federal STC rebate is calculated using your STC zone rating, a number between 1.092 and 1.622 that reflects how much sun your area gets. Zone 1 (highest rating) covers the Northern Territory and the northern tips of Queensland and Western Australia. Zone 4 (lowest) covers Tasmania. NSW, SA, and most of WA and QLD sit in Zone 3 (1.382). Victoria and ACT sit in Zone 4 (1.185, except Tasmania).
The zone rating multiplies into the STC formula:
system kW × STC zone rating × years remaining × $38.
So the same 6.6 kW system in Darwin (Zone 1) generates about 35% more in federal STC rebate than the same
system in Hobart (Zone 4).
What the data tells us
The ACT is the best place in Australia to install solar in 2026
Stack the federal STC (~$1,188) with the ACT's $15,000 Sustainable Household Loan (3% interest from 1 July 2025) plus the Home Energy Support Program rebate (up to $5,000 total, $2,500 for solar + $2,500 for efficient hot water or insulation), and the ACT consistently delivers the lowest net cost of solar in the country. The loan financing means most Canberra households pay nothing upfront and repay over 10 years from bill savings.
NT punches above its weight on federal rebate
The NT sits in STC Zone 1 with the most generous federal rating in the country. Even without a state rebate program (the NT Home Battery Scheme reached its funding cap and closed), an NT household gets meaningfully more federal STC value per kW than any other state. Combined with the NT's high irradiance (5.2 peak sun hours/day), this is the best per-kW yield in Australia.
Tasmania compensates with regulation
Tasmania sits at the bottom of the rebate stack (Zone 4, no state upfront rebate). But the state's flat regulated feed-in tariff of 8.93 c/kWh is one of the best uncapped FIT rates in the country, and the Energy Saver Loan ($10,000 interest-free) covers the upfront cost. Tasmania's per-kWh export economics over 20 years actually beat several mainland states.
WA has the most-distorted time-of-export economics
WA's DEBS feed-in scheme pays just 2.25 c/kWh off-peak but jumps to 10 c/kWh during the 3pm–9pm peak. That spread (4.4×) is the biggest in the country and makes batteries especially valuable for WA households, charge during the day, discharge into the evening peak window.
About this data
All figures are 2026 typical values, compiled from public sources (Clean Energy Regulator, state government energy departments, AER's Energy Made Easy comparison tool). Rebate amounts and FIT rates are reviewed annually; for the live picture, check the relevant state's energy department or contact us for the current stack for your postcode.
Want the underlying data? Drop us a line at hello@solarpowersavings.com.au, we publish a machine-readable JSON snapshot quarterly for journalists and researchers covering the Australian solar transition.
Common questions
What is an STC zone and why do they matter?
Australia is divided into four STC zones based on latitude and average solar irradiance. Zone 1 (NT, far north QLD/WA) gives 1.622 STCs per kW installed, the most generous federal rebate band. Zone 4 (Tasmania) gives 1.092, the lowest. Your zone is set by your postcode and determines the dollar value of your federal STC rebate.
Which Australian state gets the biggest solar rebate?
On a panels-only 6.6 kW install in May 2026, NT actually leads on federal STC alone (~$1,627 thanks to STC Zone 1). For panels + battery, the ACT pulls ahead because the $5,000 Home Energy Support Program stacks with federal STC and the federal Cheaper Home Batteries Program. NSW comes next thanks to the per-kWh PDRS battery incentive. VIC, SA, TAS, NT have no active state upfront rebates in 2026; their stacks are federal-only.
How many Australian postcodes does solar work in?
Practically all of them. We have CEC-accredited installer coverage across 2,734 residential delivery postcodes, every state and territory, every major city and most regional towns. The federal STC rebate applies to every postcode in Australia, with the rebate amount varying by STC zone.
Which state has the highest peak sun hours?
The Northern Territory leads with about 5.2 peak sun hours per day on average. Queensland and Western Australia follow with about 4.7. Victoria and Tasmania are at the lower end (3.9 and 3.7 respectively). Lower peak sun hours doesn't mean solar doesn't work, Victoria's generous state rebate stack and Tasmania's regulated FIT mean payback is comparable.