Here's something that surprises a lot of first-time solar buyers: the federal solar "rebate" gets smaller every single year — on a fixed schedule, written into law — until it disappears entirely at the end of 2030. It's called the STC phase-down, and understanding it is one of the most useful things you can do before requesting a quote.
First things first: how STCs actually work
The discount on your solar quote comes from small-scale technology certificates (STCs), created under the federal Small-scale Renewable Energy Scheme and overseen by the Clean Energy Regulator. Here's the gist:
- When you install an eligible solar system, it's entitled to a number of STCs based on how much electricity it's expected to generate over the remaining life of the scheme
- Each STC has a market value, because electricity retailers are legally required to buy them
- Rather than making you trade certificates yourself, your installer claims them on your behalf and takes their value off your quote upfront
That's why you'll rarely see "rebate" on official paperwork — it's a certificate scheme that behaves like a point-of-sale discount.
The deeming period: why the discount shrinks
The number of STCs your system earns depends on three things: its size, your location (sunnier zones earn more), and something called the deeming period — the number of years of future generation the system is credited for.
Here's the catch. The scheme has a hard end date of 31 December 2030, and the deeming period only counts the years left until then. So:
- A system installed in 2026 is deemed for the years through to the end of 2030
- The same system installed in 2027 gets one fewer year of deemed generation — so it earns fewer STCs
- Every 1 January, the deeming period drops again, and the discount steps down with it
Nothing about your system changes. Same panels, same roof, same output — but each new year, it simply attracts fewer certificates. That's the phase-down: a built-in, entirely predictable shrinking of the discount until it reaches zero after 2030.
The phase-down isn't a rumour or a sales tactic — it's legislated. But how it's used in sales pitches is worth watching, as we'll get to below.
Batteries are winding down too
If you're considering storage, note that the Cheaper Home Batteries Program rides on the same SRES machinery and also winds down towards 2030 — and according to the DCCEEW, its step-downs are now more frequent than annual, with tiered rates by battery size introduced from 1 May 2026. So the "sooner rather than later" logic applies at least as strongly to a solar battery as it does to panels. Our rebates guide keeps track of what's currently on offer federally and state by state.
What this means in practice
Two takeaways, and they pull in slightly different directions:
1. Installing sooner locks in a larger discount. This is just arithmetic. A system installed in December earns more STCs than the identical system installed a few weeks later in January. Over the remaining years to 2030, each step-down permanently shaves value you can never claw back. Exact certificate numbers and prices move with the market, so confirm current figures with your installer.
2. But never let urgency buy you a bad system. "The rebate drops in January!" is technically true every single year — which is exactly why high-pressure sales teams lean on it. A rushed decision on a poor-quality system will cost you far more over 25 years than one year's STC step-down ever could. Take the time to compare installers, check componentry, and read real customer feedback on solar reviews. Our solar tips guide covers the classic pressure tactics to watch for.
The smart play is simple: move with purpose, not panic. Start comparing quotes now, take a couple of weeks to do it properly, and you'll still comfortably beat the next step-down.
Ready to lock in this year's rate?
The phase-down means the discount on the table today is the biggest it will ever be again. Get quotes from up to 3 trusted local installers — free, no obligation — and compare them side by side before the next step-down arrives.
