Australia’s STC rules care about the inverter in one way: is it on the Clean Energy Council inverter list on the installation date. The architecture it uses is secondary.
Are string inverters STC eligible
Yes. A listed string inverter is the baseline case. Capacity and model must match the listing, and the panels must also be listed.
Are microinverters STC eligible
Yes, where the microinverter model is listed. A microinverter system has many inverters, so every unit should be the listed model. Record serial numbers consistently: the photo and form requirements still apply, and STC photo requirements covers what is needed.
Are optimisers STC eligible
Optimisers sit between panel and inverter. They are normally supplied as part of a matched system with a particular listed inverter, so the practical check is that the inverter is listed and you are using the manufacturer’s approved combination. Because list treatment of accessories can change, confirm on the CEC site and with the manufacturer before quoting.
Are hybrid inverters STC eligible
Yes, hybrids are on the inverter list like any other. If a battery is added under the Cheaper Home Batteries Program, the battery has its own list and its own rules, including VPP capability; see battery product eligibility.
Are parallel inverters STC eligible
Multiple listed inverters installed in parallel or on a shared system are fine so long as each model is listed and the total system size is correctly declared. The mistake to avoid is mixing a listed inverter with an unlisted one and assuming the listed one carries the whole claim. It does not.
Is an inverter without an export limit eligible
Export limiting is a grid-connection matter set by the distribution network, not an STC test. A listed inverter without an export limit is still eligible for STCs, but the network may refuse or restrict the connection. Sort that out before commissioning.
If you are unsure how an unusual combination is treated, such as a listed inverter with a non-listed power optimiser, ask the manufacturer for written confirmation and check the CEC site, and do not assume that because a combination is common it is accepted.
What this means for installers
Photograph the inverter label and the data plate, and make sure the serial and model match the invoice and the form. Check the approval dates as covered in what happens if a product is removed.
What this means for homeowners
Ask which inverter you are getting and why. Micro, string and hybrid each have trade-offs for shading, future batteries and warranty, but none of them changes whether you get STCs. See STC trading for how the discount works. Installers can check rates on pricing.