All you need to know about STC ‘rebates’

Last reviewed: 1 September 2026. This guide provides general information about the Australian Small-scale Renewable Energy Scheme (SRES). It is not a final eligibility determination, quote or financial advice.

If you are comparing solar proposals, you will probably see an STC rebate or STC discount deducted from the price. It can reduce the amount you need to invest upfront, but the wording often leaves an important question unanswered: what is an STC, and how is its value worked out?

This guide explains what STCs mean in solar, how the discount reaches you, what affects the number and value of certificates, and which rules apply today. It also explains the announced change that could bring larger commercial solar projects into the scheme from 1 October 2026.

The aim is simple: to give you enough clarity to compare proposals properly and make a better-informed energy investment decision.

What is an STC in solar?

STC stands for Small-scale Technology Certificate. An STC is a certificate created under the Australian Government’s Small-scale Renewable Energy Scheme for an eligible renewable-energy system. One STC represents one megawatt hour (MWh) of renewable electricity generated, stored or displaced by an eligible system.¹

You may also see the terms STC meaning, solar STCs or solar power STCs. In practical terms, the certificate value may reduce the upfront price of an eligible solar or battery installation.

Is it an STC rebate or an STC discount?

Both expressions are commonly used, but STC discount is usually the more accurate description of what appears on a solar quote.

Most system owners assign their right to create STCs to a registered agent, often through their solar retailer. In return, the expected certificate value is applied as an upfront reduction in the system price.⁵

It is not an automatic cash rebate paid directly by the government to every solar buyer. Your proposal and contract should clearly explain:

• who will create the STCs;
• the STC price or certificate value assumed in the discount;
• what evidence and signatures you need to provide; and
• what happens if the completed system or its eligibility details change.

Who currently qualifies for solar PV STCs?

Before relying on an STC rebate or discount, you need to know whether the completed system fits the scheme.

The SRES can apply to eligible household and business installations. System size is only one part of the test: the products, design, installation, electrical work and supporting documents must also meet the applicable requirements.

A system cannot be pre-approved under the SRES. Eligibility is determined after installation and application, so any STC figure provided beforehand must remain an estimate.²

What this means for a commercial solar project today

A business installing an eligible system at or below the current limit may receive an upfront benefit from STCs. That benefit can improve the project’s starting economics, but it should not be considered in isolation.

A sound commercial assessment also considers your electricity use, tariff, operating hours, usable roof area, roof condition, electrical infrastructure, network requirements and plans for the site. STCs may reduce the upfront cost; the right system design determines whether the project works for your business.

How are solar STCs calculated?

Two systems with the same panel capacity can receive different STC estimates. The main calculation inputs include:

• System capacity: the eligible rated output of the installed solar PV system.
• Postcode zone: different parts of Australia have different solar-resource ratings.
• Installation date: the year of installation determines the available deeming period.
• Deeming period: the number of future generation years recognised by the scheme.

For a solar PV system installed in 2026, the deeming period is five years. It decreases by one year annually until it reaches one year for installations in 2030.³

This is why an STC figure from a 2021 article or quote is not a reliable guide for a system installed today.

You can review the current inputs and postcode zones using the Clean Energy Regulator’s STC calculation guidance. The REC Registry calculator provides an indication only; the final entitlement depends on the completed installation and claim.

What determines the STC value shown on a quote?

The number of eligible certificates and the price applied to each certificate are separate parts of the calculation.

STCs can be traded through the open market or the STC clearing house. Open-market STC pricing is negotiated and can change with supply and demand. The clearing-house certificate price is set at $40 excluding GST, but there can be a wait for a buyer.⁴

The $40 clearing-house figure is not a guaranteed open-market STC rate and does not guarantee the value used in your quote.

Most customers do not create and sell the certificates themselves. Instead, they assign that right to a registered agent in exchange for the upfront discount.⁵ Ask for the certificate count and assumed value to be shown clearly so you can compare proposals on the same basis.

What must the system and installation comply with?

These requirements help protect you and maintain the integrity of the scheme. For a new eligible solar PV system, they include:

• an SAA-accredited designer and installer, as applicable, with the required electrical licensing for the work performed;
• eligible PV modules and inverters included on the relevant Clean Energy Council approved-product lists;
• applicable Australian Standards, grid-connection rules and installation requirements;
• installer on-site attendance and evidence requirements; and
• the signed statements and supporting documents required for the STC claim.⁶⁵

If you assign the right to create STCs to a registered agent, that assignment must also be properly documented.

What is changing for commercial solar systems above 100 kW?

Many commercial roofs can support considerably more than 100 kW of solar. Under the rules in force today, that capacity boundary changes the certificate pathway available to the project.

On 5 August 2026, the Australian Government announced its intention to expand SRES eligibility to solar PV systems with total onsite capacity above 100 kW and no more than 1 MW, for installations from 1 October 2026.⁷

If you are planning a commercial, industrial, agricultural or community project in this range, you can assess the opportunity now without assuming the outcome. Your roof, electricity demand, network pathway, project timing and final system design can be investigated while the regulatory requirements are being settled.

What could your commercial roof support?

Your available roof area is a practical starting point. For larger commercial roofs, use our Commercial STC Calculator to map the usable area and view an indicative system size before detailed energy, network and engineering assessments.

Solar-battery STCs follow different rules

Solar batteries have separate settings under the SRES. An eligible battery has a nominal capacity from 5 kWh to 100 kWh, while STCs can only be claimed for the first 50 kWh of usable capacity.⁸

Battery STC factors are based on installation date and taper according to usable capacity. Batteries do not use the solar PV deeming-period calculation.³

That means a battery estimate should be assessed separately from a solar PV estimate, even when both form part of the same energy plan.

How STCs work in three common situations

A home solar system

For a household installation, the estimated certificate count depends on the approved system design, postcode zone, installation date and available deeming period. The relevant question is not what a typical 6.6 kW system received several years ago; it is what the proposed system may qualify for under the rules applying when it is installed.

A commercial system no larger than 100 kW

For a business project within the current capacity limit, STCs may be included in the upfront-price calculation. The decision should also account for electricity consumption, tariff, available roof area, electrical capacity and network requirements.

A proposed mid-scale project

For a project above 100 kW and no more than 1 MW, the announced expansion may apply to eligible installations from 1 October 2026 if the required regulations commence. Until the final rules are in force, any STC result for that project should be described as a scenario rather than an entitlement.

STCs and LGCs: what is the practical difference?

STCs provide an upfront-style certificate benefit based on the deemed generation of an eligible small-scale system. Larger systems may be eligible for Large-scale Generation Certificates (LGCs) only after power-station accreditation and subject to Large-scale Renewable Energy Target eligibility requirements. LGCs relate to eligible renewable electricity actually generated.²

The intended mid-scale expansion may change the preferred pathway for some projects between 100 kW and 1 MW. The right answer will depend on the final regulations and the circumstances of the project.

Frequently asked questions about STC rebates

Calculate your commercial STC opportunity

If you are considering solar for a commercial roof, start with the practical information that shapes the project: usable roof area, indicative capacity and your site’s energy needs.

CALCULATE YOUR COMMERCIAL STC OPPORTUNITY

The calculator gives you a clear starting point. An Energy Advisor can then help you examine your electricity data, network pathway, project timing and the requirements applying when the system is installed.

A data-led pathway from roof opportunity to an informed commercial energy investment decision.