The question comes in two forms: “will STC prices fall as the scheme ends” and “will the STC price drop after 2027”. They deserve the same answer, which is that two opposing forces are in play.
Force one: fewer certificates
The deeming period shortens every year: 5 years for 2026 installs, 4 for 2027, then down to 1 in 2030. A typical system creates fewer STCs each January. Less supply per job, all else equal, supports price. See what changes in January 2027.
Force two: less demand
Liable entities must surrender a percentage of their electricity load each year. The small-scale technology percentage for 2026 is reported at about 11.67%, and non-binding forecasts show it falling in 2027 and 2028. Less obligation means fewer certificates needed, which pushes the other way.
Force three: new supply
The Cheaper Home Batteries Program has created STCs for batteries since 1 July 2025, and from 1 October 2026 mid-scale solar above 100 kW up to 1 MW can create them too. Both add to the pool beyond rooftop solar. See mid-scale solar STCs and the battery effect on price.
What it adds up to
| Time | Likely pressure |
|---|---|
| 1 Jan 2027 | Fewer certificates per system, plus a pre-change installer rush |
| 2027 to 2029 | Shrinking obligation versus battery and mid-scale supply |
| 2030 | Final year, deeming period at one year, scheme ends 31 December |
The most probable outcome, at the time of writing, is that spot continues to trade in the high $30s with oversupply as the main downside risk. A sharp drop at the scheme end is possible if there is a surplus in the Clearing House, and the effect of any policy extension is unknown, see scheme extension.
What this means for installers
Your decision is not whether to bet on the price, it is whether to take the risk at all. Lodge claims promptly, because deeming-period changes apply by installation date, and use a locked rate so a late-scheme slide does not reach your quotes. Read selling STCs before the deeming drops for timing, what happens in 2030 for the end date, and see today’s rate on the pricing page. The STC trading overview covers the process.