The short answer is no, and the reason is simple: both certificates represent the same thing, one megawatt-hour of renewable generation. Paying for it twice would defeat the scheme.
Two different timelines
STCs are an upfront, deemed amount. When a system is installed, the CER credits the electricity it is expected to generate over a set number of years, as a number of certificates, and the owner can sell them straight away. See the STC formula.
LGCs are created after the electricity is actually generated. A power station is accredited, meters its output and creates one LGC per MWh above its baseline, usually year by year. See creating LGCs.
Which path applies
| System size | Path at the time of writing |
|---|---|
| Up to 100 kW | STCs, declining deeming period (5 years for 2026) |
| Above 100 kW to 1 MW, installed from 1 Oct 2026 | STCs, fixed five-year deeming period (CER applications open mid to late Nov 2026) |
| Above 100 kW, installed before 1 Oct 2026 | LGCs as generated |
| Above 1 MW | LGCs |
The mid-scale solar page covers the new rule in full. For an older system above 100 kW, the usual path remains accreditation and LGCs; see commercial solar over 100 kW and LGCs.
Why the choice matters
A 150 kW system might create around 150 MWh a year. At an LGC price of roughly $6 to $9 in September 2026, that is about $900 to $1,350 a year. Under the mid-scale STC rule the same system in zone 3 could create about 150 x 1.382 x 5 = roughly 1,036 STCs, around $39,000 to $41,000 at $38 to $40 each. The two paths are not equal, so be clear which one your system sits on before you price it.
Who owns the certificates
If a third party owns the system under a power purchase agreement, the contract usually says who gets the certificates. See LGCs, PPAs and who owns certificates.
A practical test is to ask three questions about any system: what is its capacity, when was it installed, and has it already been accredited as a power station or had STCs created? The answers decide the path. If you are unsure, the Clean Energy Regulator can confirm the position for a specific system before you sell any certificates.
What this means for you
Match the system to the scheme, then choose a trader who handles that certificate type. Energy Merchants trades STCs; see STC trading, pricing and the commercial solar hub. For the basics, read LGC versus STC and the glossary entry for LGCs.