Enter Solar System Inputs
Use direct size or let panel wattage and count derive the system size automatically.
Example Data Table
| Item | Sample Value |
|---|---|
| Panel wattage | 450 W |
| Panel count | 10 |
| Derived system size | 4.50 kW |
| Gross system cost | $10,200.00 |
| Net upfront cost | $8,400.00 |
| First-year generation | 7,200.00 kWh |
| Lifecycle cost per kWh | $0.08 |
| Discounted LCOE | $0.11 |
| Estimated payback | 7 years |
Formula Used
System Size (kW) = (Panel Wattage × Panel Count) ÷ 1000
Gross Cost = Equipment + Installation + Battery + BOS
Net Upfront Cost = Gross Cost − Incentives
Year n Energy = First-Year Generation × (1 − Degradation Rate)n−1
Lifecycle Cost per kWh = Total Nominal Lifetime Cost ÷ Lifetime Generation
Discounted LCOE = Present Value of Lifetime Costs ÷ Present Value of Lifetime Energy
Avoided Utility Cost = Yearly Energy × Grid Rate
Payback occurs when cumulative yearly net benefit covers net upfront cost.
How to Use This Calculator
- Enter a direct system size, or provide panel wattage and panel count.
- Add all capital costs, including equipment, installation, battery, and mounting items.
- Subtract rebates, tax credits, or grants in the incentives field.
- Enter first-year energy production from an installer proposal or solar simulation.
- Set degradation, maintenance, inverter replacement, and lifespan assumptions.
- Add local grid price and escalation to compare solar output with avoided utility cost.
- Click Calculate to show the results above the form.
- Use the CSV and PDF buttons to export the calculated report.
FAQs
1. What does cost per kWh mean for solar?
It shows how much each generated kilowatt-hour effectively costs over time. Lower values usually indicate stronger long-term value from the solar investment.
2. Why include degradation?
Panels slowly produce less energy each year. Degradation helps the calculator estimate more realistic lifetime output instead of assuming flat production forever.
3. Why is discounted LCOE different from simple lifecycle cost?
Discounted LCOE adjusts future costs and energy to present value. Simple lifecycle cost uses nominal totals without time-value adjustments.
4. Should incentives be entered before or after taxes?
Enter the amount that actually reduces your out-of-pocket project cost. This keeps the net upfront value closer to your real purchase scenario.
5. Can this calculator include battery storage?
Yes. Add battery expenses in the battery field. That cost becomes part of the total system investment and affects the resulting cost per kWh.
6. What is the best source for annual generation?
Use production estimates from a site assessment, installer proposal, or solar modeling tool. Better generation inputs give far more reliable cost results.
7. Does payback include maintenance and replacement?
Yes. The yearly net benefit subtracts maintenance and scheduled replacement costs before checking whether the upfront investment has been recovered.
8. Is this calculator a final financial quote?
No. It is a planning tool. Actual system pricing, energy production, financing, and incentive rules can change by installer, location, and contract terms.