The solar rebate is shrinking every year: what Perth households need to know before 2030

Australia's solar rebate — the Small-scale Technology Certificate (STC) program — has a scheduled end date: 1 January 2031. The scheme doesn't just disappear overnight; it steps down by one year of "deemed" generation each calendar year from 2026 to 2030. This means the rebate shrinks by approximately 20–25% each year.

For Perth buyers considering solar in the next few years, the timing of your purchase affects your rebate value more than you might expect.

How the STC calculation works

STCs are created based on the expected electricity generation of your solar system over a set deeming period. Currently the deeming period is 4 years (in 2026). Each year after this, the deeming period drops by 1 year.

STC count formula (simplified):

STCs = System size (kW) × Deeming years × Zone rating ÷ MWh per STC

For Perth (Zone 3, zone rating 1.382), each STC represents 1 MWh of energy.

Example — 6.6kW system in Perth Zone 3:

| Year of installation | Deeming period | Approximate STC count | Approximate rebate value* | |---|---|---|---| | 2026 | 4 years | ~37 STCs | ~$1,400 | | 2027 | 3 years | ~27 STCs | ~$1,025 | | 2028 | 2 years | ~18 STCs | ~$685 | | 2029 | 1 year | ~9 STCs | ~$340 | | 2030+ | 0 years | 0 STCs | $0 |

Based on approximate STC spot price ~$38. STC spot price fluctuates — rebate values are indicative.

The rebate available in 2026 is approximately 4× the rebate available in 2029 for the same system.

What the step-down means in dollar terms

A 6.6kW Perth system losing approximately $340–$400 of rebate value per year of delay:

• Install in 2026 vs 2027: approximately $375 difference
• Install in 2026 vs 2028: approximately $715 difference
• Install in 2026 vs 2029: approximately $1,060 difference

These are real reductions in the upfront incentive — the solar system still pays back through electricity savings regardless of when you install, but your out-of-pocket cost is lower if you install sooner.

Does timing actually change the payback period?

For a 6.6kW Perth system with typical savings of $1,400–$1,800/year:

| Install year | Effective cost (after rebate) | Typical payback | |---|---|---| | 2026 | $4,100–$5,600 | 2.5–4 years | | 2027 | $4,475–$5,975 | 2.7–4.3 years | | 2028 | $4,815–$6,315 | 2.9–4.5 years | | 2029 | $5,160–$6,660 | 3.2–4.8 years |

The payback extension is modest — 3–8 months per year of delay. For most households, a year or two of delay doesn't fundamentally change whether solar makes sense. But for buyers already planning to install, there's no benefit to waiting and a clear financial incentive to proceed sooner.

The WA Battery Scheme has no step-down — but could change

The WA Battery Scheme ($130/kWh, maximum $1,300, Synergy customers only) is separate from STCs and has no scheduled step-down at time of writing. However, the scheme's continuation depends on state government policy — it could be extended, modified, or wound up at any time.

Unlike the STC program (which has a legislated end date), the Battery Scheme has no end date published. Synergy lists eligibility requirements and conditions on their website.

Common misconception: "waiting for prices to fall"

Solar panel prices have fallen dramatically over the past decade — from $10+ per watt in 2010 to approximately $0.80–$1.30 per watt today. The question is whether prices will continue to fall fast enough to offset the declining rebate.

From 2023–2026, installed solar system prices in Perth have been relatively stable. The supply-chain normalisation after COVID, increases in shipping costs, and modest wage inflation in the electrical trade have roughly offset any further panel price declines.

The calculation now: prices are unlikely to fall faster than the rebate is declining. A buyer in 2027 will pay a similar or higher installed price and receive a lower rebate — net cost increases.

The one legitimate reason to wait

If you're planning significant home changes in the next 12 months — adding a battery, installing EV charging, building an extension that might shade the roof, replacing the roof itself — waiting until those changes are complete avoids double handling of the solar system installation. A year's delay in those circumstances costs $300–$400 in rebate but saves much more in avoided re-installation costs.

STC calculations are indicative. Actual deeming periods, zone factors, and STC spot prices vary. Verify current STC eligibility and calculations with your solar installer and the Clean Energy Regulator.