People search for this in many ways: STC price 2019, 2020, 2021, a ten-year chart, a graph over time. They all want the same thing, which is the shape of the market. Here it is, with the caveat that I am describing ranges, not publishing daily prints.
The structure that explains the chart
Since 2011 the Clean Energy Regulator’s Clearing House has bought certificates at a fixed $40. That sets a ceiling: nobody pays more on the open market when they can buy at $40. Spot has therefore lived below $40, and the gap to the ceiling reflects supply, demand and the cost of waiting for payment. Read spot versus Clearing House for the mechanics.
Year by year, in ranges
| Year | Rough picture |
|---|---|
| 2019 | Mid to high $30s, a strong solar year |
| 2020 | High $30s, pandemic disruption but steady rooftop installs |
| 2021 | Close to the ceiling, a record year for installations |
| 2022 | Near the ceiling, firm demand and tight supply |
| 2023 | At or near $40 until late in the year |
| 2024 | Started around $39.30, softened early in the year, then recovered |
| 2025 | Close to $39.90 early in the year; battery certificates added supply |
| 2026 | Roughly $38 to $40 at the time of writing |
These are indicative ranges. For exact figures use the regulator’s quarterly carbon market reports, which give quarterly averages, or a broker’s historical series.
What drove the movement
- Installation volume. Record rooftop installs in 2020 and 2021 added certificates.
- Deeming period. It shortens each year, so each system creates fewer STCs than the year before.
- Heat pumps and batteries. Growth in state-scheme heat pump claims in late 2023 and the federal battery program from July 2025 added new supply. See oversupply and battery certificates.
- Surplus in the Clearing House. When it holds a queue of unsold certificates, spot tends to soften.
How to read a price chart
Look at the spread to $40, not the dollar level. A move from $39.80 to $39.30 is small in dollars but significant relative to a $40 cap. Also ask who is quoting: a spot price is not the rate a trader pays you.
What this means for installers
Use history to judge whether a rate is reasonable, not to guess the next move. For current numbers see the pricing page, what an STC is worth in 2026 and the daily and weekly price question. The certificate trading glossary explains the terms.