Solar Battery STCs Explained
Under the federal Cheaper Home Batteries Program, home batteries are discounted through small-scale technology certificates (STCs), not a flat percentage. Your estimated STCs are your usable capacity (up to 50 kWh) run through a capacity taper and multiplied by a dated STC factor that declines over time. The dollar value depends on the certificate market.
How STCs reduce battery cost
STCs are certificates created when an eligible battery is installed. Your installer typically applies their value as an upfront discount. The number of STCs is worked out from your usable capacity via a taper, then multiplied by the STC factor for your installation date:
- 100% of the factor on the first 14 kWh of usable capacity;
- 60% of the factor from 14–28 kWh;
- 15% of the factor from 28–50 kWh;
- capacity above 50 kWh earns no additional STC support.
The STC factor declines over time
The factor steps down through 2030, so installing earlier generally yields more STCs for the same battery. Current dated schedule:
| Installation period | STC factor |
|---|---|
| May–Dec 2026 | 6.8 |
| Jan–Jun 2027 | 5.7 |
| Jul–Dec 2027 | 5.2 |
| Jan–Jun 2028 | 4.6 |
| Jul–Dec 2028 | 4.1 |
| Jan–Jun 2029 | 3.6 |
| Jul–Dec 2029 | 3.1 |
| Jan–Jun 2030 | 2.6 |
| Jul–Dec 2030 | 2.1 |
Turning STCs into dollars
Each STC has a market value that moves over time and is influenced by your installer's arrangement. That's why our estimator shows your STC count first and only converts to dollars if you enter a certificate price. Try it in the battery discount estimator.
Unofficial — confirm your entitlement
Sources
- Cheaper Home Batteries Program Department of Climate Change, Energy, the Environment and Water (DCCEEW) · Last checked 20 September 2026
- REC Registry — Small-scale Technology Certificate calculators Clean Energy Regulator — REC Registry · Last checked 20 September 2026