Solar Payback & ROI Calculator
Assumes all generated electricity is valued at the entered tariff.
This selection changes review context only. Formulas and example inputs stay unchanged. Check the model assumptions and applicability for the actual process.
Identify the actual asset, process, work boundary, source documents, units and assumptions. Confirm that the selected model or template applies before using its results.
1 Inputs
Minimum: 0.1
Minimum: 0
Minimum: 0
Minimum: 100
Minimum: 0
Minimum: 0 · Maximum: 100
Minimum: 0
Minimum: 0 · Maximum: 100
Minimum: 1 · Maximum: 40
Minimum: 0
2 Results
Simple payback
9.2 yrs
Net cost after 0% credit
$450,000
25-yr lifetime savings
$1,670,483
Net present value (NPV)
$344,053
Return on investment
271%
Capital cost / lifetime energy
$0.055/kWh
Iₙ = I(1−c); PB = Iₙ/S₁; NPV = Σ Sₜ/(1+r)ᵗ − Iₙ
Assumes all generated electricity is valued at the entered tariff. Incentives default to zero and require confirmation. Capital cost per lifetime kWh excludes operating costs, so it is not full LCOE; verify yield, self-consumption and export tariffs.
Worked example
Example values are illustrative. Replace them with your measured data.
| Input | Value |
|---|---|
| System size | 250 kW |
| Cost entry | $ per watt |
| Installed cost ($/W) | 1.8 $/W |
| Total installed cost | 450000 $ |
| Specific yield | 1400 kWh/kW/yr |
| Electricity rate | 0.14 $/kWh |
| Incentive / credit (confirmed) | 0 % |
| Utility escalation | 3 %/yr |
| Panel degradation | 0.5 %/yr |
| Analysis period | 25 yr |
| Discount rate | 6 % |
Simple payback: 9.2 yrs