Adding a battery to a system you installed years ago is one of the most common upgrades, and it is eligible for its own certificates. The earlier STCs for your panels and the new STCs for the battery are separate claims.
What the program covers
The Cheaper Home Batteries Program started on 1 July 2025 and gives STCs to batteries with a usable capacity from 5 kWh to 100 kWh, with up to 50 kWh counted. It works with new or existing solar. Your battery must be on the CEC-approved list, be capable of joining a virtual power plant (VPP), and be installed by an accredited installer. One battery per property is eligible. New photo and evidence rules have applied since 1 March 2026.
How the discount is worked out
STCs = usable capacity in kWh, tiered, multiplied by the factor for the installation date.
- First 14 kWh at 100% of the factor
- 14 to 28 kWh at 60%
- 28 to 50 kWh at 15%
These tiers have applied since 1 May 2026. The factor is 6.8 for May to December 2026, stepping down to 5.7 on 1 January 2027 and 5.2 on 1 July 2027, and continuing to fall to 2030.
Worked example at the time of writing: a 10 kWh battery installed in 2026 earns 10 x 6.8 = 68 STCs. At roughly $38 to $40 each that is about $2,600 to $2,700 before the installer’s margin on the rate, which is a significant slice of the price. Use our battery STC calculator for your battery size.
Things to check when you already have solar
- Inverter compatibility. An old inverter may not talk to a modern battery. A hybrid swap or an AC-coupled battery may be needed.
- Solar size. It does not need to be large, but your battery will perform better with decent solar.
- VPP. The battery must be capable of joining a VPP, and some state schemes require you to be enrolled. WA’s scheme, for example, requires VPP participation.
- Installer accreditation. See who can install batteries.
- Timing. Waiting means a lower factor, so check the January 2027 step before you delay.
Other incentives
Some states have their own battery incentives, though several have closed, such as the NT scheme and Queensland’s Battery Booster. See stacking STCs with state rebates for how they sit with the federal program.
What this means for you
If you already have solar, the battery discount stands on its own. Get a quote that shows the number of STCs, the factor and the value per STC, like a solar quote. Run the battery STC calculator first, and read the homeowners guide. Installers can see how battery claims settle in battery STCs and our pricing.