Commercial Solar STCs for 100 kW to 1 MW: What Businesses Need to Know
Last reviewed: 3 September 2026
If your business has a large roof and significant daytime electricity use, the opportunity may extend well beyond a 100 kW solar system. The question is how to prepare responsibly while the proposed rules for mid-scale solar are still being finalised.
The Australian Government has announced its intention to expand the Small-scale Renewable Energy Scheme (SRES) to eligible solar PV systems above 100 kilowatts (kW) and no more than 1 megawatt (MW). The change is intended to apply to qualifying systems installed from 1 October 2026, subject to regulations being in place.
That qualification is essential. Businesses can investigate their roof, electricity data, network pathway and project timing now. They should not treat a future Small-scale Technology Certificate (STC) result as an entitlement, quote or guaranteed financial outcome.
For a broader explanation of how STCs work, including certificate calculations, quote discounts, current eligibility and compliance, read our complete guide to STC rebates and discounts.
Current rules and the announced proposal
Two positions need to be kept separate.
The rules currently in force
Current Clean Energy Regulator guidance says an eligible solar PV system under the SRES must have:
- a rated capacity of no more than 100 kW; and
- annual electricity output of no more than 250 megawatt hours (MWh).
Capacity and output are not the only conditions. Products, design, installation, electrical work and claim evidence must also satisfy the applicable requirements.
SRES systems cannot be pre-approved. Eligibility is assessed after installation and an application is received. Any certificate figure shown during project planning must therefore remain an estimate.
The announced mid-scale proposal
The proposed expansion concerns solar PV systems with total onsite capacity above 100 kW and no more than 1 MW. The Government intends the change to apply to mid-scale solar installed from 1 October 2026, but only if the required regulations are in place.
The Clean Energy Regulator says additional design, installation and compliance requirements are being considered. It also says commencement and eligibility information will be published before the change takes effect.
The CER says applications will not open until mid to late November 2026, when the required systems and processes are in place, and assessment will begin after that time. The intended 1 October 2026 installation treatment remains subject to regulations being made. Businesses should not assume that an STC claim pathway will be operational on 1 October merely because that is the intended installation date.
What the proposed pathway could require
The Department of Climate Change, Energy, the Environment and Water says the proposed criteria include:
- a maximum system size of 1 MW for new installations;
- a maximum combined capacity of 1 MW for expansions to existing systems;
- installer and product accreditation requirements under the SRES;
- a written installer statement;
- compliance with state and territory electrical-safety requirements; and
- compliance with relevant planning approvals and network-connection agreements.
The Department also says the proposed STC factor for mid-scale solar would be based on a five-year deeming period each year to 2030.
These remain proposed settings. They must not be converted into a promised certificate quantity, dollar value, rebate, discount or project entitlement before the regulations and implementation pathway are available.
What your business can responsibly do now
Waiting for final rules does not mean putting all project work on hold. A business can make useful progress on the parts of the project that will matter under any responsible commercial-solar pathway.
Review usable roof area and structural feasibility
Roof area is a starting point, not a final system capacity. Roof shape, setbacks, shading, access, plant equipment, skylights, fire requirements, roof condition and structural capacity can all affect what is practical.
Early roof and structural assessment can identify constraints before they become redesigns or construction variations.
Analyse interval data and daytime demand
Interval data shows when the site imports electricity and how demand changes across the day, week and year. It helps test whether a larger solar system aligns with the way the business actually uses energy.
Annual consumption alone is not enough. System planning should consider load timing, tariffs, operating hours, seasonal patterns, future demand and the potential effect of exports.
Prepare a preliminary system design
A preliminary design can connect usable roof area with the site’s electrical demand and physical constraints. It can help establish a sensible capacity range without presenting that range as a final design or approved STC outcome.
Investigate the network pathway
Network requirements can affect exports, protection, equipment, engineering, timing and cost. Larger projects may require a more detailed connection process than smaller rooftop systems, so this work should begin early.
Plan project timing and conditional commercial options
Businesses can review roof works, electrical upgrades, tenancy considerations, planning requirements, procurement lead times and construction windows now.
Commercial proposals prepared before the framework is operational must clearly separate confirmed project costs and assumptions from any conditional STC scenario. Eligibility, certificate quantity, certificate value, claim acceptance and commencement timing must not be guaranteed.
What cannot be treated as operational yet
The proposed mid-scale STC pathway should not be treated as operational until:
- the required regulations are made and in force;
- the Clean Energy Regulator publishes the applicable implementation and eligibility guidance;
- the required CER systems and processes are available; and
- a usable registered-agent pathway is available for the project.
Energy Partners uses Formbay for certificate processing. Formbay readiness will be operationally important, but an aggregator or software platform cannot override the legislation or the Clean Energy Regulator’s requirements.
Indicative STCs are only one part of the decision
For an eligible SRES system, STCs may contribute to an upfront discount when the system owner assigns the right to create certificates to a registered agent.
For the proposed mid-scale pathway, it is too early to rely on a final certificate count or value. The more useful question is:
Does this roof, energy profile and network pathway justify detailed investigation if the proposed pathway becomes available?
That keeps the investment decision grounded in the business and the site rather than a headline certificate figure.
STCs and LGCs: the practical distinction
STCs and Large-scale Generation Certificates (LGCs) are both part of the Renewable Energy Target, but they operate differently.
STCs are generally created after installation for an eligible SRES system using deemed generation or displacement. LGCs are created by accredited power stations for eligible renewable electricity that has actually been generated and measured.
Under the current framework, solar systems above 100 kW may fall within the Large-scale Renewable Energy Target pathway. The Clean Energy Regulator says existing accredited large-scale systems will remain under current LRET arrangements if the mid-scale proposal proceeds. A project’s pathway should be assessed from the operative rules and its particular circumstances, not capacity alone.
Commercial solar preparation checklist
Before relying on a future certificate pathway, establish:
- the roof area that remains usable after access, setbacks and physical constraints;
- the building’s structural condition and any engineering requirements;
- the site’s interval-data load profile, tariffs and likely future demand;
- a technically sensible preliminary system-capacity range;
- the network, electrical, planning and approval pathway;
- the effect of project timing, procurement and construction constraints; and
- which financial assumptions are confirmed, estimated or conditional.
Start with your roof opportunity
Our Commercial STC Calculator helps you map usable commercial roof area and explore an indicative system capacity and certificate scenario.
The calculator is a planning tool. It is not a quote, system design, eligibility determination or guaranteed STC outcome.
An Energy Advisor can then connect the roof opportunity with your interval data, site constraints, network pathway and the requirements applying when the system is installed.
A data-led pathway from roof opportunity to an informed commercial energy investment decision.
Frequently asked questions
Can a commercial solar system above 100 kW claim STCs today?
Do not assume that it can. Current CER guidance limits solar PV systems under the existing SRES pathway to no more than 100 kW and no more than 250 MWh annual output. The proposed above-100-kW pathway remains subject to regulations and implementation guidance.
Does the proposal apply automatically to every system up to 1 MW?
No. The proposal concerns solar PV above 100 kW and no more than 1 MW, but the final eligibility, evidence, design, installation and implementation requirements must still be confirmed. Site-specific approvals and the network pathway also matter.
Can we start planning before the pathway opens?
Yes. Businesses can review interval data, usable roof area, structural feasibility, preliminary design, network requirements and project timing. This work should preserve flexibility and must not assume a future STC entitlement.
Can I use the calculator result as a quote or STC entitlement?
No. The calculator provides an indicative planning scenario. Final eligibility and certificate outcomes depend on the completed installation, the rules in force, the available claim pathway and the supporting evidence.
Is 1 October 2026 a guaranteed commencement or application date?
No. It is the Government’s intended installation date for the proposed change, subject to regulations being made. The CER says applications will not open until mid to late November 2026, when the required systems and processes are in place, and assessment will begin after that time.
What if a project is already being considered under the LRET?
Do not assume it should move pathways. The CER says existing accredited large-scale systems will remain under LRET arrangements. Obtain project-specific advice before changing an accreditation or development approach.
Official sources
- Clean Energy Regulator: Expansion of solar PV eligibility under the SRES, reviewed 3 September 2026.
- Department of Climate Change, Energy, the Environment and Water: Renewable Energy Target scheme, reviewed 3 September 2026.
- Clean Energy Regulator: Eligibility for the Renewable Energy Target, reviewed 3 September 2026.
- Clean Energy Regulator: Small-scale renewable energy systems, reviewed 3 September 2026.
- Clean Energy Regulator: Calculate small-scale technology certificate entitlements, reviewed 3 September 2026.
- Federal Register of Legislation: Renewable Energy (Electricity) Regulations 2001, reviewed 3 September 2026.