Introduction
One of the biggest questions solar households face is whether to invest in a battery or simply choose a plan with a higher feed-in tariff (FiT). Both options can improve your solar savings, but the better choice depends on your usage patterns and goals.
For background, see What is FiT? or compare offers at Retailer Rates.
Key Definitions
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Battery storage: Stores daytime solar for evening use or export at peak times.
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Feed-in tariff (FiT): Payment per kWh exported to the grid.
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Round-trip efficiency: The percentage of energy a battery returns after charging and discharging (typically 85–90%).
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Opportunity cost: Comparing what you’d earn by exporting vs what you save by self-consuming.
Worked Example 1 — Higher FiT Plan
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Export: 400 kWh/month
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Flat FiT = 10c/kWh
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Monthly credit: 400 × $0.10 = $40
If your household exports most of its solar, a higher FiT boosts savings without upfront investment.
Test this using the FiT Savings Calculator.
Worked Example 2 — Battery for Evening Use
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Export avoided: 200 kWh used in evening instead of buying at 30c/kWh
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Battery efficiency: 90% → 180 kWh usable
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Savings: 180 × $0.30 = $54
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Compare to exporting those 200 kWh at 10c/kWh = $20
Battery use saves more, but only after considering battery cost.
Model payback with the Solar ROI Fit Calculator.
Worked Example 3 — Mixed Scenario
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Half exports at 10c = $20
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Half stored in battery → evening savings = $27
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Combined monthly benefit = $47
Long-term results depend on how FiT rates and tariffs change over time. Track changes with the Rate Change Tracker.
Who Benefits from Each Option?
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Higher FiT plan: Best for households with low evening use and high daytime exports.
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Battery: Best for households with high evening usage or time-of-use import tariffs.
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Hybrid approach: Some families benefit from both — modest battery use plus higher FiT credits.
Check what works best in your region with the Postcode Estimator or Compare FiT by State.
FAQs
Q1. Is a battery always better than a higher FiT?
Not always. Batteries involve upfront costs and only pay off if evening usage or tariffs are high.
Q2. How do I calculate payback for a battery?
Use tools like Solar ROI Fit to model years to break even.
Q3. Can I switch between FiT plans easily?
Yes, most retailers allow plan changes, but always check Retailer Rates first.
Q4. Do falling FiT rates make batteries more attractive?
Yes, lower FiTs make self-consumption and battery storage more valuable.
Conclusion
The choice between battery or higher FiT depends on your household’s energy profile. If you export a lot during the day, a higher FiT plan is simple and effective. If your usage peaks at night or tariffs rise sharply, a battery could deliver greater long-term value.
Run your own numbers with the FiT Savings Calculator and test scenarios with the Solar ROI Fit before deciding.