STCs, explained.

01What an STC is

STC stands for small-scale technology certificate. It's the federal government's incentive for rooftop solar, run by the Clean Energy Regulator under the Small-scale Renewable Energy Scheme.

When a solar system is installed, it earns a number of certificates. Each certificate stands for a megawatt-hour of clean electricity the system is expected to make. Electricity retailers are required to buy certificates each year, which is what gives them a value.

02How you receive it

Almost nobody sells their own certificates. You sign them over to your solar retailer, and in exchange their value comes off the price of your system on the day. It appears on a proposal as a line taken off the total.

So although people call it a rebate, there's nothing to claim afterwards and nothing to wait for. If you've had a price for solar in Australia, the incentive was almost certainly already in it.

It isn't a rebate you claim. It's a discount that's already in the price.

03How the number is worked out

Three things are multiplied together: the size of the system in kilowatts, a rating for where you live, and the number of years left in the scheme.

The rating reflects how much sun your part of the country gets. Australia is divided into four zones, and Melbourne is in zone four. A bigger system earns more certificates, and the same system earns more in Darwin than it does here.

04Why it shrinks every year

The scheme ends on 31 December 2030, and a system only earns certificates for the years between its installation and that date. A system installed during 2026 is credited with five years. Installed in 2027, four. Then three, two, and in 2030, one.

The step happens on 1 January each year, and it's a large one: a system installed on the second of January earns a fifth fewer certificates than the same system installed a few days earlier. Each later January the step is bigger again in proportion. After 2030 there are none.

What a certificate is worth also moves, because it's a market price. It's the count that falls on a fixed timetable.

05Who is eligible

There's no means test. Homes and businesses both qualify, and so do rental properties and holiday houses. The system has to be new, no larger than 100 kilowatts, built from panels and inverters on the Clean Energy Council's approved lists, and installed by an accredited installer.

Adding panels to an existing system counts too: the added capacity earns certificates for the years that remain. The certificates have to be created within twelve months of the installation.

06What decides which year you're in

The date that counts is the day the system is installed, not the day you sign. A system ordered in November and installed in January is a January system.

That's worth knowing when you plan, and it's why installers' calendars fill at the end of each year. It isn't a reason to rush a decision you're not ready for. A well-designed system installed a few months later is still a better buy than a poor one installed in time.

The schedules and rules here were checked against the Clean Energy Regulator and Solar Victoria in October 2026. Both change from time to time, so read them at the source before you rely on them.