Analyze utility offsets, export value, and ownership returns. Test rates, incentives, costs, and long-term assumptions. Plan smarter solar economics with clear yearly projections today.
Year 1 generation = System size × Specific yield
Self-used solar = Year generation × Self-consumption rate
Exported energy = Year generation − Self-used solar
Energy savings = Self-used solar × Grid import rate
Export credits = Exported energy × Export compensation rate
Gross annual benefit = Energy savings + Export credits
Net annual benefit = Gross annual benefit − Maintenance − Replacement cost
Net upfront cost = Installation cost − Rebates − Tax credits
NPV = −Net upfront cost + Σ(Net annual benefit ÷ (1 + Discount rate)year)
ROI = (Lifetime net savings ÷ Net upfront cost) × 100
Simple payback is the point where cumulative cash flow first becomes positive.
IRR is the discount rate that makes total project NPV equal zero.
| Scenario | System Size | Annual Generation | Import Rate | Export Rate | Year 1 Net Benefit | Simple Payback |
|---|---|---|---|---|---|---|
| Urban home | 6 kW | 8,400 kWh | $0.16 | $0.09 | $1,080 | 8.7 years |
| Suburban home | 8 kW | 11,600 kWh | $0.18 | $0.10 | $1,652 | 7.9 years |
| Small business | 15 kW | 21,750 kWh | $0.21 | $0.11 | $3,256 | 6.8 years |
It measures how much money a solar system saves through avoided grid purchases and export credits, compared against ownership costs over time.
Self-consumed solar usually offsets electricity at the full retail rate. That often creates more value than exported energy under reduced compensation rules.
Choose the full retail option. The calculator will treat exported electricity the same as imported electricity for year-by-year bill credit valuation.
Solar output slowly declines over time. Modeling degradation makes long-range savings and payback estimates more realistic than flat production assumptions.
It converts future savings into present-day value. This helps compare a solar investment with other uses of your money.
Yes. Fixed utility charges are added to the pre-solar bill. They usually remain even when solar offsets most energy charges.
Low export credits, high installation cost, weak solar yield, or heavy maintenance assumptions can keep cumulative cash flow below zero.
Yes. Enter commercial tariffs, export credits, consumption, and project costs. The model works for many residential and small commercial cases.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.