Mid-scale solar STCs: 100 kW to 1 MW

What changed on 1 October 2026

For most of the scheme's life the Small-scale Renewable Energy Scheme stopped at 100 kW. Anything bigger had to be accredited as a power station under the Large-scale Renewable Energy Target and earn large-scale generation certificates on what it actually generated, one year at a time. For a 200 kW warehouse roof that meant metering, accreditation and a trickle of certificates over many years, and plenty of owners decided the paperwork was not worth it. The industry calls this the missing middle.

In 2026 the Australian Government amended the Renewable Energy (Electricity) Regulations 2001 to bring solar PV systems over 100 kW and up to 1 MW into the small-scale scheme. The Clean Energy Regulator announced the expansion in August 2026, published transitional guidance on 1 October 2026, and keeps the detail on its mid-scale solar page, last updated 7 October 2026. Everything on this page comes from those documents and the regulator's entitlement rules.

Who is eligible

• Size. Solar PV over 100 kW and up to 1 MW. Systems of 100 kW and under were already in the scheme, and nothing changes for them.
• Install date. Installed on or after 1 October 2026. An earlier install is not a mid-scale system, whatever its size.
• Components and installer. Panels, inverters and any battery must be on the Clean Energy Council's approved lists, and the installation must meet Solar Accreditation Australia's guidelines, the same as a rooftop job.
• One site, several systems. The regulator says guidance on how related devices and power stations at the same site are counted together is still to come. Until it arrives, treat a site that already has a solar system or an accredited power station as a question for the regulator, not an assumption.
• Transition projects. If a project was planned under the old rules, the regulator asks for transition issues to be raised no later than a week after mid-scale applications open.
• Deadline. As with every STC claim, the certificates can be created within 12 months of the installation date.

A fixed five-year deeming period

A small-scale system is deemed to generate for the years left until the scheme ends in 2030, so its certificates shrink every January. A mid-scale system gets a fixed five-year deeming period instead. The regulator's entitlement page, updated 29 October 2026, puts the two side by side:

The gap widens every January, so which side of the 100 kW line a design falls on now changes what the customer gets. How the deeming period falls, year by year.

How many STCs: an estimate

The regulator has not published a mid-scale formula on its pages. It points to its own mid-scale STC calculator and calls the result a guide only. For small-scale panels the rule is kW x zone rating x deeming years, rounded down. If the same method applies with five years, the figures look like this:

Our estimate, from the small-scale method with a five-year deeming period and the zone ratings in the federal instrument. Zone 3 covers Sydney, Brisbane, Perth and Adelaide; zone 4 covers Melbourne and Hobart. Check it against the regulator's calculator before you quote. Dollar figures use our published price for scale only; read the last section before you rely on them for a mid-scale job.

Commercial system owners are usually registered for GST, so the owner's assignment is a taxable supply and the owner issues a tax invoice. On our price table that is the business row: $37.27 + $3.73 GST = $41 per STC. GST on STCs explains the difference.

On a home system our $41 is above the $40 clearing house cap, and the regulator advises caution with prices above that cap. What to check in any trader, including us.

STCs or REGO certificates

A mid-scale owner has a choice the rooftop market never had. They can take the scheme's upfront benefit through STCs, or take part in the Renewable Electricity Guarantee of Origin scheme and receive REGO certificates instead. Choosing STCs means no REGO certificates can be created for the deeming period.

In cash terms, STCs are paid once, up front, through an agent or trader. REGO certificates arrive over time and depend on a market that is still forming, so they suit an owner who can wait and wants to hold the certificates. The regulator's page sets out the choice without recommending either, and so do we. What matters for a retailer is that the choice is made before the paperwork, because an assignment form that hands the STC right to an agent cannot be undone later.

When claims open, and the paperwork

The regulator says STC applications for mid-scale systems open in mid to late November 2026, with assessment starting after that. A system installed in October 2026 is not losing time: the 12 months to create certificates runs from the installation date.

Expect the same evidence as a rooftop claim, at scale:

• an STC assignment form naming the registered agent, the deeming period and the financial incentive
• the designer's, installer's and retailer's written statements
• the state's electrical safety certificate, and in WA the Notice of Completion as well
• every panel and inverter serial number, with geotagged photos of the install and the installer on site

Serial numbers are the part that grows with the system. A 500 kW roof can carry more than a thousand panels, so decide who scans them, and how, before install day. What each claim needs.

What it means for retailers and installers

• New jobs become worth quoting. A factory or school roof between 100 kW and 1 MW now gets an upfront discount instead of a slow trickle of large-scale certificates, which changes the payback the customer sees.
• The January cliff does not apply. A fixed five years means a job that slips from December into January loses nothing on deeming, unlike a rooftop job. It also means the two sides of the 100 kW line now earn very different numbers, so be sure which side a design falls on.
• GST is the normal case, not the exception. Most owners at this size are GST-registered businesses. Price the job on the GST-inclusive figure and get the tax invoice right.
• The money is bigger, so the trader matters more. A single claim can run to thousands of certificates. The clearing house is capped at $40 before GST with no promise of when a certificate sells, and the money a trader owes you is your exposure to that trader. Check any trader before you assign a claim this size.

We buy STCs from eligible systems across Australia. Mid-scale claims are new for everyone, including us, so talk to us about a mid-scale job before you quote it rather than assume our published price: we will tell you what we can do, and when. How selling STCs works.