The short version: some of the solar that would have created LGCs will now create STCs instead, and that is a modest supply shift in a market that is already well supplied. The details matter for owners of LGC-earning plant and for anyone modelling commercial solar returns.
What the change does
Before 1 October 2026, a solar system above 100 kW had to be accredited as a power station and create large-scale generation certificates (LGCs) for each MWh generated above the baseline. For systems installed from 1 October 2026, those above 100 kW and up to 1 MW create small-scale technology certificates (STCs) up front with a fixed five-year deeming period. Systems above 1 MW remain in the LGC scheme. See mid-scale solar STCs.
Supply effect on LGCs
Every mid-scale system that picks the STC path creates no LGCs over its life. Because that band is a small share of total LGC volume, which is dominated by utility-scale wind and solar, the volume effect is small. It reduces the pipeline of new LGC creators at the margin. The LGC market already has plenty of supply: the verified spot price was roughly $6 to $9 in September 2026 after a low near $4 in February, and $11 at the start of Q4 2025. Never treat those as current quotes. Check a live source on the day.
Does it move price?
Honestly, nobody can say with confidence. Lower future supply is supportive of price, but demand is set by the Renewable Power Percentage obligations, and a market that is oversupplied for other reasons will not tighten because of a band of rooftop systems. Treat any claim of a price jump as speculation.
Existing LGC systems
Systems already accredited keep creating LGCs. Owners of systems close to 1 MW or near the date should check with the Clean Energy Regulator about which scheme applies, and whether the install date or accreditation date governs. For how LGCs are created, see create LGCs and LGC vs STC.
STC or LGC: which is better for a project?
| STCs (100 kW to 1 MW) | LGCs | |
|---|---|---|
| Timing | Value at install | Per MWh, over the years |
| Price risk | Taken at sale of the STCs | Carried for each year |
| Admin | One claim | Ongoing metering and creation |
| 2026 market | About $38 to $40 | About $6 to $9 |
Because the two certificates are priced very differently per MWh, an STC upfront will usually look more attractive than a stream of cheap LGCs. That is a hint about which way mid-scale solar will go.
What this means for installers and owners
If you sell commercial systems, the proposal should show the STC value and drop the LGC forecast for any job in the new band. If you own an LGC-generating system, the change affects your future competitors more than your existing income. Get the numbers for your size in STCs for 200 kW to 1 MW and read what installers need to know.
For selling certificates see STC trading and pricing.