Solar Panel System Output & Battery ROI Calculator
Estimate solar PV generation, self-consumption savings, feed-in tariff revenue, and payback period.
Input Parameters
Standard Australian residential systems are 6.6 kW (with 5 kW inverter)
Perth/Brisbane ~4.8-5.2, Sydney/Adelaide ~4.4-4.6, Melbourne/Hobart ~3.8-4.2
Net out-of-pocket price after Federal STC solar rebates
Percentage of solar energy consumed inside the home during daytime (without battery: 30-50%; with battery: 70-90%)
Calculation Results
Visual Growth Breakdown
Formula & How Solar Panel System Output & Battery ROI Calculator Works
A solar photovoltaic (PV) array converts solar irradiance into direct current (DC) electricity, converted by an inverter to 240V AC. Self-consumed electricity offsets expensive grid imports (typically 28–38¢/kWh), while excess electricity exported to the grid earns a feed-in tariff credit (typically 4–8¢/kWh).
- Enter Solar Array System Size (kW) (kW): Input your target parameter value.
- Enter Average Daily Peak Sun Hours (hrs/day): Input your target parameter value.
- Enter Net Installed System Cost ($ AUD) ($): Input your target parameter value.
- Enter Grid Electricity Tariff (¢/kWh) (¢/kWh): Input your target parameter value.
- Enter Solar Feed-in Tariff FiT (¢/kWh) (¢/kWh): Input your target parameter value.
- Enter Solar Self-Consumption Rate (%) (%): Input your target parameter value.
- Apply Formula: Calculate using
Annual kWh = kW × Sun Hours × 365 × η | Savings = (Self-consumed kWh × Grid Rate) + (Exported kWh × FiT) | Payback = Cost ÷ Annual Savings. - Review Results: View exact computed answers, metrics, and worked mathematical proofs.
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Frequently Asked Questions (FAQs)
How long does a 6.6 kW solar system take to pay for itself in Australia?
In most Australian states, a standard 6.6 kW solar PV system costs between $4,500 and $6,500 after STC rebates and achieves a full return on investment (payback period) within 3.5 to 5.5 years.
How does adding a battery storage system affect solar ROI?
A home battery (e.g. 10–13.5 kWh) increases daytime solar self-consumption from ~45% up to 80–95% by storing afternoon excess for night usage, reducing peak grid import fees.
Authoritative Standards & Verified Reference Citations
Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:
Consumer guidance on mortgage borrowing capacity, compound interest formulas, and loan fees.
Official cash rate target announcements, monetary policy statements, and national economic statistical data.
Residential mortgage serviceability buffer framework (3.0% stress test hurdle rate).
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