Installers ask for an STC price forecast because they quote jobs weeks ahead and want to know whether the number will hold. The honest answer is that no one can forecast it with confidence, and anyone who sells you a precise figure is guessing. What can be done is to list what moves the price, say which way each factor pushes, and build a quoting habit that works across all outcomes.
This article does that. It is not a prediction. At the time of writing the STC spot market has been roughly $38 to $40, against a clearing house ceiling of $40. Everything below is framed against that starting point.
The hard limits
Two facts bound the problem.
The ceiling. The CER’s STC Clearing House buys at a fixed $40 per STC, ex GST. The market price cannot sustainably exceed this, so upside is capped at a few percent from where it sits. Our explainer on the clearing house versus trading prices covers why.
The end date. The scheme ends on 31 December 2030, and the deeming period shortens each year: five years for 2026 installs, four for 2027, down to one in 2030. This limits how many certificates can ever be created.
With upside capped and the scheme finite, the question is mainly how far below $40 the price can fall and why.
Factors that could push the price down
- Supply outruns demand. If installation volumes, including batteries, create more certificates than liable entities need to surrender, the spare supply pushes the price lower, or into the clearing house queue.
- A lower Small-scale Technology Percentage. The CER sets the percentage each year from expected generation. A lower number reduces demand.
- Slower processing. If the registry validates certificates more slowly, traders hold stock longer and price in that cost.
- Policy shocks. Changes to eligibility or the scheme itself can create uncertainty, and uncertainty is priced.
Factors that could hold or lift it
- Shorter deeming. Each January the same install creates fewer certificates. Fewer certificates per job means less new supply.
- Retailer demand. Liable entities that fall short face penalties, so they buy.
- The ceiling itself. With a firm $40 limit and a long queue behind it, there is limited incentive for a trader to price much lower unless it is buying certainty.
- Battery factor decline. The battery STC factor falls from 6.8 to 5.7 per kWh on 1 January 2027 and to 5.2 on 1 July 2027 and keeps declining to 2030, so battery supply per kWh falls too. See the battery factor for 2027.
Three scenarios
These are illustrations to stress-test your quoting, not predictions.
| Scenario | Spot range | What would have to be true |
|---|---|---|
| Steady | $38 to $40 | Supply and demand stay balanced, as in 2026 so far |
| Soft | $34 to $37 | Strong install volumes, including batteries, outpace demand |
| Tight | $39 to $40 | Falling deeming reduces supply; liable entities need certificates |
Run your margin through each. Take a 6.6 kW system in a 1.382 zone with five years of deeming, about 45 STCs.
- Steady at $39: 45 x $39 = $1,755
- Soft at $35: 45 x $35 = $1,575
- Tight at $40: 45 x $40 = $1,800
The spread between the soft and tight cases is $225 per job. On 40 jobs a month, that is $9,000. That sounds large, but if you sell each job at a locked rate when you lodge, the market’s swing is not yours to carry past that point. The exposure is in what you quote before you lodge. See our STC calculator answer for the arithmetic by zone.
How to quote without a forecast
You do not need to predict the price. You need to decide how much of it you will promise.
- Quote at a conservative rate. Use a figure a dollar or two below spot. If the market holds, you keep the difference.
- Show the STC discount as a separate line. Customers understand a line that can change by a few dollars before install, and you can note on the quote that it is based on a stated rate.
- Shorten your quote validity. A 14-day quote cuts the window of exposure. Quotes valid for 60 days carry real price risk.
- Lock on lodgement. Choose a trader whose rate is locked as soon as you lodge a complete claim, so risk ends at lodgement instead of at settlement.
From the desk: Be wary of any forecast that comes with a product to sell. A trader who says prices will fall and urges you to sell forward at a fixed rate may be right, or may be selling you a price that suits them. Ask what happens if the price rises, and whether you can see the contract before you decide.
What changes at 1 January 2027
Some of the most predictable moves are the scheduled ones. The deeming period drops to four years for 2027 installs, and the battery factor falls to 5.7. Installers often bring jobs forward to claim under the current rules, which can create a surge in certificates in the fourth quarter. A surge could press on prices briefly. Read what changes in January for the specifics, and plan your pipeline accordingly.
Where to look
For market facts, use the CER’s Quarterly Carbon Market Report, the registry data and published trader rates. For history, see STC price history. For the cost components inside a rate, see STC pricing explained.
Why forward selling is not a free hedge
Selling certificates forward at a fixed price feels safe, and for some businesses it is. If you have financed stock or need to commit to a price on a large commercial job, a forward deal gives certainty. But forward prices typically sit a little below spot to pay the buyer for taking on time and risk, so you give up a small amount in return for removing the downside. If the market is already pinned near the $40 ceiling, there is little upside to give up, and a modest discount for certainty may be sensible. If the market looks soft, a fixed price protects you. Just be clear about delivery dates, quantities and what happens if a job slips, because a forward contract is a commitment to deliver certificates you may not yet have created.
What to do next
- Check today’s number on the pricing page and note the date you quoted against it
- Test your margin in the soft scenario: if the job still works at $35, you are comfortable
- Review your quote validity period
- Read how it works to see when a rate is locked and when you are paid