Solar Battery Payback Calculator

Post-1 May 2026 tiered rebate

Solar Battery Payback Calculator

See your real payback period under the federal battery rebate — correctly valuing self-consumption vs export.

The federal Cheaper Home Batteries Program knocks roughly 30% off an eligible battery upfront — but the rebate is no longer a flat per-kWh discount. Since 1 May 2026, it tapers by battery size, and the real payback math depends on something most quick calculators get wrong: the value of a battery isn't the full retail electricity rate, it's the gap between what you'd pay the grid and the small feed-in tariff you'd otherwise earn exporting that same energy.

kWh
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Please enter the battery's usable capacity to calculate.
$
$
› Adjust STC price / rebate assumptions (optional)
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Rebate uses the post-1 May 2026 tiered STC Factor automatically based on your battery size.
Estimated payback period
0 years
After the federal rebate is applied.
Federal rebate
$0
Net cost after rebate
$0
Annual saving
$0
Value per kWh shifted
$0
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Missing battery size

Please enter the battery's usable capacity before calculating — it's the required field.

How the federal rebate actually works now

The Cheaper Home Batteries Program pays out as Small-scale Technology Certificates (STCs) your installer creates and sells — it shows up as a point-of-sale discount, no application needed. But since 1 May 2026, the rebate tapers by battery size instead of applying one flat rate to the whole system.

The tiered STC Factor (from 1 May 2026)
0-14 kWh usable: 100% of the base rate (6.8 STC/kWh)
14-28 kWh usable: 60% of the base rate
28-50 kWh usable: 15% of the base rate
Above 50 kWh usable: $0 — no further STC discount
Worked example — 13.5 kWh battery, $13,500 cost: rebate ≈ 13.5 × 6.8 × $37 ≈ $3,394, leaving a net cost of about $10,106. The factor steps down again every 6 months, so installing sooner locks in today's higher rate.

The mistake most battery calculators make

A battery doesn't turn every kWh of stored solar into a full retail-rate saving. Without the battery, that excess midday solar would still be exported and earn the feed-in tariff — just a small one. The battery's real value per kWh is the spread between what you'd pay to buy that energy back from the grid at night and what you'd have earned exporting it instead.

The correct payback formula
Value per kWh shifted = retail rate − feed-in tariff
Annual saving = usable capacity × value per kWh × cycle days/year
Payback = (cost − rebate) ÷ annual saving
At $0.32/kWh retail and $0.06/kWh feed-in, each kWh shifted is worth $0.26 — not $0.32. Using the full retail rate instead of the spread overstates annual savings and understates the real payback period.

Why the rebate timing matters

The STC Factor for batteries over 14kWh drops every six months, with the next cut on 1 January 2027. If you're considering a larger system, installing before a step-down date locks in the higher rate for that install — waiting doesn't get you a better deal, just a smaller rebate.

Check for stacking state incentives

Some states still offer add-on incentives that stack with the federal program — for example, NSW's PDRS VPP incentive for batteries connected to an approved Virtual Power Plant. Several states (VIC, QLD, SA, TAS, NT) have closed their own standalone battery rebates and now rely on the federal program only. Always check current state-specific offers before assuming a state rebate still applies.

For the panels-only side of solar economics, see the Solar Savings Calculator, and for the broader electricity cost picture, the electricity bill calculator.

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Frequently asked questions

How much is the federal home battery rebate worth in 2026?+
For the first 14 kWh of usable capacity, roughly $252 per kWh as of after 1 May 2026 (down from about $311/kWh before that date). Capacity between 14-28 kWh gets 60% of that rate, 28-50 kWh gets 15%, and anything above 50 kWh gets no further discount.
Do I need to apply for the battery rebate myself?+
No. Your accredited installer handles it — they create and sell the Small-scale Technology Certificates and apply the value as a point-of-sale discount on your invoice. There's no separate application and no means test.
Why isn't my battery saving the full retail electricity rate per kWh?+
Because without the battery, that stored solar energy would still be exported and earn the feed-in tariff — a small amount, but not zero. The battery's real value is the gap between the retail rate and the feed-in tariff, not the full retail rate.
Should I size my battery to get the maximum rebate?+
Not necessarily. The tiered structure specifically discourages oversizing — capacity above 14 kWh gets a much smaller rebate per kWh, so a bigger battery than you actually need can hurt your payback period rather than help it. Size to your actual evening/overnight usage, typically 10-16 kWh for most households.
Is now a good time to install, or should I wait for a bigger rebate?+
The rebate steps down every six months, not up — the next cut is 1 January 2027. Waiting gets you a smaller rebate, not a bigger one. The factor is locked in based on your installation date.
Can I add a battery to my existing solar system?+
Yes. The federal rebate applies to retrofit battery installations on existing solar systems as well as new combined solar-and-battery installs, as long as the battery itself meets the eligibility criteria.
Does my state offer an extra battery rebate on top of the federal one?+
It depends on your state. NSW offers a VPP-connection incentive that stacks with the federal rebate; Victoria, Queensland, South Australia, Tasmania and the Northern Territory have closed their standalone battery rebates and now rely on the federal program only. Always confirm current offers with your installer.
This calculator provides general estimates only and is not financial advice. It models the federal Cheaper Home Batteries Program's tiered STC rebate as published for the period from 1 May 2026, using an estimated STC price after typical admin costs. It does not include state-specific incentives, VPP payments, network tariff structures, or battery degradation over its warranty life. Confirm current figures with an accredited installer before purchasing.

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