A small-scale technology certificate. Each one represents one megawatt-hour of electricity your system is assumed to produce over its deeming period. Your installer or an agent sells them and takes the value off your price, so the “rebate” appears as a lower price on the quote.

How are STCs worked out for systems up to 100 kW?

System size in kW, times the solar zone rating for your postcode (MWh per kW per year), times the deeming period, rounded down. The deeming period is the number of years left until the scheme ends in 2030: 5 for 2026, 4 for 2027, then 3, 2 and 1.

Do systems over 100 kW get STCs?

From 1 October 2026, systems over 100 kW and up to 1 MW can, with a fixed 5-year deeming period. Before that date they could not. Systems over 1 MW are not part of the STC scheme; they can instead be accredited as a power station to create large-scale generation certificates (LGCs).

When can mid-scale systems apply for STCs?

The Clean Energy Regulator says applications for mid-scale STCs do not open until mid to late November 2026. Eligibility depends on the date the system was installed, so a system commissioned on or after 1 October 2026 can still apply once applications open.

Why is my quote’s rebate different from this estimate?

The installer may use a different certificate price, a different system size (panel capacity, not inverter), or a slightly different zone. Ask for the number of certificates and the price per certificate behind the discount on your quote.

Does the rebate shrink every year?

For systems up to 100 kW, yes: the deeming period falls by one year each January until the scheme ends in 2030. The installation date counts, not the date you sign. For mid-scale systems the period is fixed at 5 years.

Free tool

STC calculator: solar rebate for homes and businesses

Work out how many certificates a solar system earns and what they are worth. Covers home systems, business systems up to 100 kW, and the new mid-scale rules for 100 kW to 1 MW from 1 October 2026.

System size

The panel capacity (kW) on the quote, not the inverter. A typical home system is 6.6 kW; a shop is 30 kW; a factory roof 100 kW or more.

Postcode of the installation

The postcode sets the CER solar zone, which sets how much electricity the system is assumed to make.

Month it will be installed

The date the system is first able to produce and deliver electricity (the commissioning date), not the date you sign.

Price per certificate

Agents usually pay $33 to $38; the government clearing house pays $40, excluding GST. Your installer sets the price they use, so ask them.

Your certificates

Add a size and a postcode

Enter the system size and the postcode (or pick a solar zone) to see the estimate.

An estimate from the Clean Energy Regulator’s published rules, rounded down to whole certificates. It is not a quote. For the official figure use the REC Registry STC calculator (systems up to 100 kW) or the CER mid-scale STC calculator (over 100 kW up to 1 MW).

Want to see what the rebate does to a business’s payback? Try the commercial solar calculator, or read our guides on mid-scale STCs and STCs, LGCs and REGOs.

Questions about STCs

What is an STC?: A small-scale technology certificate. Each one represents one megawatt-hour of electricity your system is assumed to produce over its deeming period. Your installer or an agent sells them and takes the value off your price, so the “rebate” appears as a lower price on the quote.
How are STCs worked out for systems up to 100 kW?: System size in kW, times the solar zone rating for your postcode (MWh per kW per year), times the deeming period, rounded down. The deeming period is the number of years left until the scheme ends in 2030: 5 for 2026, 4 for 2027, then 3, 2 and 1.
Do systems over 100 kW get STCs?: From 1 October 2026, systems over 100 kW and up to 1 MW can, with a fixed 5-year deeming period. Before that date they could not. Systems over 1 MW are not part of the STC scheme; they can instead be accredited as a power station to create large-scale generation certificates (LGCs).
When can mid-scale systems apply for STCs?: The Clean Energy Regulator says applications for mid-scale STCs do not open until mid to late November 2026. Eligibility depends on the date the system was installed, so a system commissioned on or after 1 October 2026 can still apply once applications open.
Why is my quote’s rebate different from this estimate?: The installer may use a different certificate price, a different system size (panel capacity, not inverter), or a slightly different zone. Ask for the number of certificates and the price per certificate behind the discount on your quote.
Does the rebate shrink every year?: For systems up to 100 kW, yes: the deeming period falls by one year each January until the scheme ends in 2030. The installation date counts, not the date you sign. For mid-scale systems the period is fixed at 5 years.

Sources

Checked 31 October 2026. This page is general information, not financial, tax or legal advice. Rules, rebates and prices change, so check the sources before you decide.

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