Solar Cashflow Calculator

Plan solar cashflow for construction site assets confidently. Include incentives, loans, degradation, and operating costs. See payback, NPV, and IRR before approving budgets final.

Project Inputs

Enter project and financial assumptions, then calculate yearly cashflows.

Toggle for planning-level tax effects. Consult a professional for compliance.

Example Data

Input Example Value Notes
System Size100 kWTypical mid-sized facility roof array.
Total Installed Cost$120,000Includes design, panels, inverters, labor.
Year 1 Production1,500 kWh/kWVaries by site irradiance and layout.
Self-Consumption80%Higher where daytime loads are steady.
Utility Rate$0.18/kWhEnter your blended energy charge rate.
Loan Portion60%Debt share of initial project cost.

Formula Used

  • Annual Production: Productiony = Size(kW) × kWh/kW × (1 − Degradation)(y−1)
  • Energy Split: SelfUsedy = Productiony × Self%, Exportedy = Productiony − SelfUsedy
  • Rates Escalation: Ratey = Rate1 × (1 + Escalation)(y−1)
  • Annual Savings: Savingsy = SelfUsedy × UtilityRatey
  • Export Revenue: ExportRevy = Exportedy × ExportRatey
  • Loan Payment (annuity): Payment = P × r / (1 − (1+r)−n)
  • Net Cashflow: Nety = Savings + ExportRev − O&M − Replacement − LoanPayment − Tax + Credits + Salvage
  • NPV: NPV = Σ Nett / (1 + DiscountRate)t
Notes: Tax is applied only on positive annual taxable benefit in this planning model. If interest shielding is enabled, loan interest reduces taxable benefit.

How to Use This Calculator

  1. Enter system size, installed cost, and the analysis period.
  2. Set production and degradation using your site estimate.
  3. Add utility and export rates, including escalation assumptions.
  4. Include incentives, tax credit percentage, and financing details.
  5. Set annual O&M and any major replacement cost year.
  6. Press Calculate Cashflows to view results above the form.
  7. Use Download CSV for spreadsheets and Download PDF for reports.

Cashflow planning for construction energy budgets

Solar cashflow analysis turns engineering inputs into numbers for capital approval. This calculator estimates annual production, splits self-use and exports, and escalates energy prices. The output is a year-by-year benefit stream for comparing roofs, carports, and ground arrays. Equity need is calculated after rebates and debt proceeds, helping align procurement with funding.

Production, tariffs, and performance drivers

Value is created mostly through avoided utility purchases, so self-consumption is the strongest driver. Exported energy is valued separately and may be compensated at a lower tariff, reducing returns when loads are mismatched. Degradation reduces output each year, while escalation increases savings and export revenue over time. Run sensitivity checks on these inputs to bound risk.

Operating costs and lifecycle allowances

O&M costs are modeled from a Year 1 baseline and escalated annually. Including periodic replacements prevents optimistic payback results, especially where inverters or switchgear require mid-life refresh. For construction facilities, consider cleaning frequency, monitoring, and access costs, because dust and temporary site conditions can affect performance and service needs.

Financing structure and simplified tax treatment

Debt can improve cashflow resilience but adds loan payments. The calculator uses a level-payment amortization and can optionally apply an interest tax shield in taxable benefit. The tax approach is simplified for planning: tax is applied only when annual taxable benefit is positive. Confirm incentives and compliance rules with your finance team before commitments.

Example scenario data for quick validation

Example inputs: 100 kW system, $120,000 installed cost, 25-year analysis, 1,500 kWh/kW Year 1, 0.6% degradation, 80% self-consumption, $0.18/kWh utility with 3% escalation, $0.08/kWh export with 2% escalation, $1,800 O&M Year 1 with 2.5% escalation, 60% loan at 7.5% for 10 years, $9,000 replacement in Year 12, and $4,000 salvage at Year 25. Use these values to verify outputs and exports.

FAQs

1) What does self-consumption mean in this model?

Self-consumption is the share of solar production used onsite to offset utility purchases. Higher self-consumption usually increases savings because avoided utility rates are often higher than export compensation.

2) Why do utility and export rates have escalation inputs?

Rates can change due to fuel costs, regulation, and inflation. Escalation helps reflect long-term pricing trends so projected cashflows remain realistic across the full analysis period.

3) How is the loan payment calculated?

The calculator uses a level-payment annuity schedule. Each payment includes interest on the remaining balance plus principal repayment until the loan term ends.

4) What is the difference between NPV and IRR?

NPV discounts future cashflows at a chosen rate to show today’s value. IRR is the rate that makes NPV equal to zero, representing an implied return for conventional cashflows.

5) How does degradation affect results?

Degradation reduces annual production slightly each year. Over long periods, even small degradation rates reduce total energy and savings, affecting payback and discounted metrics.

6) Why include replacement and salvage value?

Major equipment may require mid-life replacement to maintain performance. Salvage value reflects remaining asset value at the end of the analysis period, improving end-year cashflow realism.

7) Can I use this output for final financial reporting?

Use it for planning and comparison. Final reporting should follow your accounting policy, incentives, and tax rules, and should be reviewed by qualified finance and compliance professionals.

Related Calculators

Solar ROI CalculatorSolar Payback CalculatorSolar Payback Period CalculatorSolar Break Even CalculatorSolar Savings CalculatorSolar Bill Offset CalculatorSolar Net Savings CalculatorSolar Lifetime Value CalculatorSolar NPV CalculatorSolar IRR Calculator

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.