Australian homes with a 20 kWh battery but no rooftop solar could save AUD 1,377-2,202 (~ $980-1,568) a year by charging it in the free midday hours of solar sharer tariffs, according to an IEEFA briefing note. A 5 kWh apartment battery could save AUD 366-644 (~ $261-459) a year, though plug-in systems face regulatory hurdles in Australia.
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IEEFA, a US-based non-profit energy finance research institute, says Australia's new solar sharer tariffs create a new opportunity for homes without rooftop solar to charge a battery from the grid. In a September briefing note by energy finance analyst Jay Gordon, IEEFA found that a household with a 20 kWh battery and no solar could save AUD 1,377-2,202 (~ $980-1,568) a year by filling it during the free midday window, provided its main appliances are electric.
The federal Solar Sharer Offer (SSO) was launched in July 2026. It requires retailers in regions covered by the Default Market Offer to provide a plan with three free hours of electricity each day in New South Wales, South Australia and South-east Queensland. Victoria's version, the Victorian Midday Power Saver (VMPS), takes effect in October 2026. Both carry a 24 kWh daily cap on free use, and IEEFA found that a small number of battery scenarios approached or slightly exceeded it.
The note cautions that this does not necessarily make a battery without solar cost-effective. According to IEEFA, a 20 kWh battery and inverter can cost more than AUD 22,000 (~ $15,660) installed without the Cheaper Home Batteries Program rebate, a payback of 10 years or more even on the best available tariff. IEEFA also modelled a 5 kWh battery in a typical apartment without solar and put its savings at AUD 366-644 (~ $261-459) a year. Plug-in batteries of that size sell for under €1,000 (AUD 1,631) in Germany, and at similar prices the payback in Australia would be 2.5-4.9 years, but regulatory and standards hurdles keep such products from wide use.
For homes that already have solar and a battery, the regulated tariffs gave mixed results, with no savings in Brisbane, some in Sydney and Adelaide and considerable savings in Melbourne. The best market plans did far better, which IEEFA attributes to some of them adding a premium evening feed-in tariff for battery exports. More than 500,000 Australian homes have installed a battery since the Cheaper Home Batteries Program launched in 2025, yet less than a quarter of battery owners are signed to virtual power plant programs that enable exports, the note says.
IEEFA recommends a federal review of the rules that block plug-in solar and battery systems. It also wants the Australian Energy Regulator and Victoria's Essential Services Commission to consider a regulated minimum evening feed-in tariff and alternatives to the 24 kWh cap when they revise the schemes.
IEEFA is a non-profit institute that examines issues related to energy markets, trends and policies, with the stated mission of accelerating the transition to a diverse, sustainable and profitable energy economy.