Commercial solar above 100 kW and up to 1 MW can now qualify for STCs

What changed on 1 October?

The federal Small-scale Renewable Energy Scheme has been expanded to cover eligible solar PV systems above 100 kW and no more than 1 MW.

Before this change, the familiar upfront STC pathway stopped at 100 kW. Larger commercial systems generally sat on the large-scale side of the Renewable Energy Target, with a different certificate process and more administration.

For eligible systems installed from 1 October 2026, that 100 kW boundary is no longer the end of the STC scheme.

Who does this affect?

This is mainly a commercial and community-scale change. Think warehouses, factories, logistics sites, farms, schools, hospitals, retail buildings and community facilities with enough daytime electricity demand and roof space to justify a system larger than 100 kW.

It does not mean every business should suddenly install 500 kW of solar. System size still needs to follow interval data, roof constraints, network approval, export limits and the site's future electricity use.

Our commercial solar sizing guide explains why a business system should be built around the load profile rather than a round number or the maximum rebate threshold.

Mid-scale systems get a fixed five-year deeming period

The expanded scheme uses a fixed five-year deeming period for eligible mid-scale solar each year through to 2030.

That is different from the declining deeming period that applies to solar systems up to 100 kW as the SRES approaches its scheduled end in 2030.

In practice, the STCs can provide an upfront financial benefit rather than making the business wait for certificates based on future metered generation. The exact dollar benefit still depends on the system, certificate calculation and STC value at the time. It should be shown transparently in the proposal rather than treated as a guaranteed percentage discount.

The rules are live, but applications are not open yet

There is an awkward timing detail for projects being installed right now. The Clean Energy Regulator says STC applications for mid-scale systems are expected to open in mid to late November 2026.

Eligible systems installed on or after 1 October can apply once that process opens. So an October installation is not automatically excluded just because the application system is still being prepared.

Businesses signing a contract now should make sure the quote clearly explains who will create the STCs, how the benefit is being assigned, and what happens if the project turns out not to meet the scheme requirements.

Projects can choose between STCs and REGOs

The Clean Energy Regulator says participants installing solar in the mid-scale range can choose between the upfront STC pathway under the SRES and the Renewable Electricity Guarantee of Origin, or REGO, framework.

That choice is worth getting right before certificates are created. A commercial project should not assume the upfront option is automatically best without checking the project economics and the certificate rules that apply.

What does this change for a Melbourne commercial solar project?

It removes one of the old financial and administrative cliffs around 100 kW. A business that genuinely needs 150 kW, 300 kW or more can now assess that size without immediately losing access to the STC pathway simply because it crossed 100 kW.

The federal government says the expansion could cut installation costs for larger rooftop systems by around 20 per cent. Treat that as a government estimate, not a promise for every project. Network works, switchboard upgrades, roof access, engineering, export constraints and the final STC value can move the real number considerably.

For Victorian businesses there can also be other incentive and project-design questions alongside the federal scheme. See the commercial solar rebates guide for the current Victorian and federal picture, and the commercial grid-connection guide before assuming a large rooftop can export whatever it generates.