Solar Panels Adelaide

STC Mechanics

The Australian solar rebate is actually an STC certificate scheme.

When you install solar in Australia, your system generates Small-scale Technology Certificates (STCs) that the installer sells. The discount you see on your invoice is the STC value. Understanding how STCs work helps you read quotes correctly.

The short answer

Each STC equals 1 MWh of expected generation over the system's deeming period. The STC value is set by the open market and typically sits between $30 and $40. In May 2026 it is around $37. STC quantity per system depends on system size, location zone, and current deeming period.

How STCs are calculated

STCs awarded = (system size in kW) x (zone rating) x (deeming period in years).

Adelaide is Zone 3 with a rating of approximately 1.382 kWh per kW per year. The deeming period is 10 years in 2026, reducing 1 year annually until the scheme ends in 2030.

Example: 6.6kW Adelaide system in May 2026

= 6.6 x 1.382 x 10

= ~91 STCs (rounded to whole STCs)

At $37/STC: ~$3,370 worth of STCs. After admin / clearing house fees (~5-10%), the customer typically sees ~$2,200-$2,600 discount on the invoice.

Note: STC accumulation calculators online may show slightly different numbers depending on roundings and the date-specific deeming year boundary.

How the STC value moves

STC prices are set by supply and demand in the STC spot market. When solar uptake spikes (excess STC supply), prices fall. When the government adjusts the Renewable Energy Target binding obligation, prices can spike.

Historical range: $20-$40/STC over the past 5 years. Currently stable around $35-$38.

The rebate value to YOU is locked in at the time your installer claims the STCs (typically within 30-60 days of install). If STC prices rise during your install window, your installer may pass through the upside (rare). If they fall, your installer usually absorbs the loss.

STC scheme end-date and what happens then

The Small-scale Renewable Energy Scheme is legislated to end on 31 December 2030. After that date:

  • New solar installs no longer receive STC rebate
  • Existing systems already installed are unaffected
  • The federal government has not announced a successor program

The deeming period steps down each year between now and 2030:

  • 2025: 11 years
  • 2026: 10 years
  • 2027: 9 years
  • 2028: 8 years
  • 2029: 7 years
  • 2030: 1 year (final partial-year deeming)

So your rebate value drops every 1 January. Buy earlier to capture more.

STC Rebate: questions

Should I claim STCs myself?

Almost no household does. The administrative overhead (registering with the Clean Energy Regulator, joining a clearing house, market timing) is not worth it for a household. Take the upfront discount from your installer.

Do battery systems generate STCs too?

Yes, under the new Cheaper Home Batteries Program (launched 1 July 2025). Batteries generate STCs at approximately $311/kWh equivalent in May 2026. Same upfront-discount mechanism as solar STCs.

Can my installer rip me off on STCs?

Yes - some quote a discount lower than the actual STC value. To check: STC count x ~$35 should approximate the discount shown on your invoice. If the discount is much smaller, ask why.

Solar Panels Adelaide is a lead-generation and referral service operated by Loudachris Digital Marketing. We do not install or sell solar systems. All installers in our network are Clean Energy Council (CEC) accredited and hold valid SA Electrical Contractor's licences under the Plumbers, Gas Fitters and Electricians Act 1995. Small-scale Technology Certificate (STC) eligibility requires CEC-accredited installation per the Clean Energy Regulator. Solar feed-in tariffs and rebates are subject to change and are determined by your retailer and government policy. Information on this site is general only; we recommend obtaining 3 quotes and comparing system specifications and warranties.

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