Nobody can tell you what the STC price will be in 2027, and anyone who offers a single number is guessing. What can be done is to understand the forces that move it, set out the realistic range and work out what each outcome is worth per job. That is more useful to an installer than a forecast, because it tells you how much price risk you are actually carrying.
At the time of writing, the spot market has been roughly $38 to $40 per STC and the regulator’s clearing house pays a fixed $40 ex GST. The ceiling is firm, the floor is uncertain and the most important change in 2027 is not price at all: it is the number of certificates each system earns. This article lays out the drivers and three scenarios. For the current rate, see our pricing page.
The ceiling: $40
The clearing house is a fixed-price buyer of last resort at $40 ex GST. Because sellers can always get $40 there (eventually), and buyers can always buy at $40, the spot market sits at or below it. That makes the 2027 question one-sided: how far below $40 will the market trade, and for how long? It is a question about discounts to the ceiling, not about spikes above it.
Driver 1: supply of certificates
STCs enter the market whenever eligible systems are installed. Three things move supply in 2027:
- Deeming period. From 1 January 2027 the solar deeming period falls from five years to four, so each solar system earns about 20 per cent fewer certificates. A 6.6 kW zone 3 system drops from 45 to 36.
- Installer volumes. A December 2026 rush, as households install before the cut, would pull certificates forward into 2026 and leave a quieter early 2027.
- Batteries. The Cheaper Home Batteries Program has added a large new source of certificates since July 2025. The factor falls from 6.8 to 5.7 per kWh on 1 January 2027 and to 5.2 on 1 July 2027, so each battery earns fewer certificates, but battery volumes may remain high.
Driver 2: demand from retailers
Demand is set by law. Each year the regulator publishes a Small-scale Technology Percentage that determines how many certificates retailers must surrender relative to their electricity sales. The percentage is set using the regulator’s forecast of certificate creation, so in principle it tracks supply. In practice, forecasts miss, and the gap between forecast and reality is one of the main reasons the spot price moves under $40. Check the regulator’s published percentage for 2027 when it is available rather than relying on commentary.
Driver 3: market timing
STC prices move seasonally and around deadlines. Rushes ahead of a deeming cut can flood supply into a particular quarter. Retailers also buy through the year, and quarterly surrender dates create demand pulses.
Three scenarios
| Scenario | Spot range | What it looks like |
|---|---|---|
| Tight market | $39 to $40 | Supply falls with the deeming cut, demand holds, spot hugs the ceiling |
| Balanced | $38 to $39 | Roughly where the market has been trading |
| Soft market | $35 to $37 | Strong battery and solar volumes, retailers well supplied |
These ranges are illustrations of how far spot might sit below the ceiling, not forecasts. A wider fall is possible but would need a sustained supply surplus.
What each scenario is worth per job
Combine price with the certificate count. A 6.6 kW zone 3 system:
| 2026 (45 STCs) | 2027 (36 STCs) | |
|---|---|---|
| At $40 | $1,800 | $1,440 |
| At $38 | $1,710 | $1,368 |
| At $36 | $1,620 | $1,296 |
The pattern is clear. The change in certificate count (about $340 a job at $38) is far larger than the change from any plausible movement in price (about $90 a job either side of $38, in the scenarios above). The deeming period, not the market, is the main driver of the 2027 rebate on a solar quote. See STC deeming period 2027: what changes in January.
For a 13.5 kWh battery, the count falls from 91 to 76 STCs when the factor changes, a difference of about $570 at $38.
What it means for quoting
- Build quotes on a price you can lock. Do not assume the headline $40.
- Quote by installation year. A job installed in 2027 earns the 2027 count, even if signed in 2026.
- Add a price-movement clause or buffer for long-lead jobs.
- Prefer a buyer whose rate is locked on lodgement, so the price risk you carry is days, not weeks.
The scheme’s end
The Small-scale Renewable Energy Scheme ends on 31 December 2030, with the deeming period falling by one year each January until then. Prices near the end may behave differently, since certificates created in the last years carry short deemed lives. Nothing about 2027 depends on that, but long-term plans should recognise it. The answer on when the STC scheme ends explains the schedule.
Reading the signals as 2027 approaches
You do not need a model to watch the market sensibly. Four public signals are enough.
- The daily rate card. If your buyer’s published rate drifts down over several weeks, supply is outrunning demand. If it sits close to $40, the market is tight.
- The regulator’s quarterly data. The Clean Energy Regulator publishes how many certificates were created and how many went through the clearing house. A rising clearing house share tells you sellers are choosing the fixed $40 over the open market, which suggests buyers are not paying close to it.
- Installation activity. A December surge is visible in your own pipeline and in industry commentary. It tends to be followed by a quieter period.
- The 2027 liability percentage. When the regulator sets it, compare it with its own forecast of certificate creation. A percentage set against high supply forecasts supports demand.
None of these predicts a price, but together they tell you whether to be cautious with quotes or relaxed.
What installers can do about price risk today
If you lock the rate when you lodge a complete claim, your exposure is the days between sale and lodgement, not the weeks to payment. If you sell certificates through a trader with a published daily rate, you can compare it against the clearing house $40 and see the gap for yourself. And if you quote jobs months ahead, build a margin of a dollar or two per certificate into the price. On 45 STCs, that is $45 to $90 a job: cheap insurance against a soft quarter, and a small bonus when the market holds.
What to do next
Track the daily rate on the pricing page and read what an STC is worth in 2026 for the current picture. For the mechanics of how rates and settlement work, see STC trading explained and the STC trading pillar. Our answers on the STC price today and STC calculator 2027 keep a short view.