Stacking is the reason NSW battery buyers can end up with a lower price than the federal rebate alone suggests, and the question comes in two forms: can the two be combined, and can an old battery benefit? The answer to both is usually yes, with conditions.
The two pieces
Federal STCs. From 1 July 2025 the Cheaper Home Batteries Program creates STCs for eligible batteries of 5 to 100 kWh usable, with up to 50 kWh counted. The battery must be CEC-approved, VPP-capable, and installed by an accredited installer; one battery per property, new or existing solar. The STC factor was 6.8 at the time of writing (May to December 2026), stepping down to 5.7 on 1 January 2027 and 5.2 on 1 July 2027. Since 1 May 2026 the first 14 kWh counts at 100 per cent of the factor, 14 to 28 kWh at 60 per cent and 28 to 50 kWh at 15 per cent. See the battery STC pillar.
NSW PDRS. The NSW battery incentive moved into the federal program in 2025, with the earlier PDRS battery activity (BESS1) reported as suspended from 1 July 2025. What remains is a PDRS incentive for connecting a battery to a virtual power plant (VPP), described in BESS2 and the NSW VPP incentive. It creates PRCs and is paid for the VPP commitment, not the hardware.
Can they be combined
They are not mutually exclusive, because they pay for different things. Federal STCs reward installation. PRCs reward the VPP connection. A NSW customer with a qualifying battery and VPP contract can have both. They still need separate evidence and separate claims: the STC claim goes to the Clean Energy Regulator, the PRC claim through a NSW accredited certificate provider. See stacking the federal rebate with the NSW battery incentive.
What about an existing battery
Two cases:
- Federal STCs on an existing battery. The rebate applies to batteries installed from 1 July 2025 under the program, so a battery already installed before then does not qualify, and the install date is the one that counts. Adding a second battery at the same property is not allowed under the one-per-property rule.
- NSW VPP incentive on an existing battery. The PDRS VPP incentive has been open to some existing batteries, subject to rules on capacity, age or remaining warranty, and a qualifying VPP contract. These rules have changed several times, so confirm with the scheme and the VPP provider.
What this means for installers
Check the sequence. Put the STC discount on the quote, flag the VPP incentive as a separate item, and say who claims it. Do not delay the STC claim waiting for VPP paperwork. See the installer guide to the program and the battery submission guide.
What this means for homeowners
Ask which incentives the quote includes, who holds the VPP contract and what the contract term is. A VPP can mean the provider controls your battery at times.
For how battery STCs get paid, see STC trading and pricing.