Live Demo — Economic Analysis Calculator
Input investment, operating and benefit parameters to receive payback, NPV and LCOE indicators instantly.
Economic Analysis Calculator
Free professional economic analysis calculator for solar street lighting projects. Enter your equipment, installation and other costs, annual maintenance and battery replacement spending, grid electricity price, annual generation, system lifetime and discount rate to compute initial investment, annual operating cost, annual net savings, payback period, net present value, levelized cost of energy and an overall economic rating.
Key Features
Investment Costs
Combine equipment cost (panels, batteries, controllers, luminaires), installation cost and other project costs into the initial investment.
Operating Costs
Capture annual maintenance, battery replacement cost and its replacement cycle, plus the grid electricity price used for savings valuation.
Savings & Benefits
Estimate annual electricity savings from the system's annual energy generation valued at the grid price, minus operating costs.
Payback Period
Compute how many years of net savings are needed to recover the initial investment (PP = C_initial / S_annual).
NPV & Discounted Cash Flow
Discount future savings back to today with your chosen discount rate and net them against the initial investment to get NPV.
LCOE & Economic Rating
Get a simplified levelized cost of energy and an excellent/good/fair/poor rating based on payback, NPV and IRR benchmarks.
Technical Specifications
| Platform | HTML5 Web App | Android (via WebView) |
| Core Calculation | C_initial = C_equipment + C_installation + C_other; S_annual = E_annual × P_grid - C_operating; PP = C_initial / S_annual; NPV = Σ(S_annual / (1 + r)^t) - C_initial; LCOE = C_initial / (E_annual × n_life) + C_operating / E_annual |
| Equipment Cost | $100 - $14,000 |
| Installation Cost | $50 - $7,000 |
| Other Costs | $0 - $2,800 |
| Annual Maintenance | $10 - $1,400/year |
| Battery Replacement | $100 - $2,800 (cycle 3 - 10 years) |
| Grid Electricity Price | $0.10 - $0.50/kWh (US avg $0.18, EIA 2026) |
| Annual Generation | 100 - 10,000 kWh/year |
| System Lifetime | 10 - 30 years |
| Discount Rate | 5% - 15% |
| Industry Standards | ISO 15686-5, ASTM E833, NREL LCOE Methodology |
| Output | Initial investment, annual O&M, annual net savings, payback (years), NPV (USD), LCOE (USD/kWh), economic rating |
Frequently Asked Questions
How is the payback period computed?
The payback period is the initial investment divided by the annual net savings (PP = C_initial / S_annual), where annual net savings is generation valued at the grid price minus operating costs. It tells you how many years of surplus are needed to recover the project outlay.
What does net present value (NPV) mean?
NPV sums every year's net savings discounted to today's value at your discount rate, then subtracts the initial investment. A positive NPV means the project adds value over its lifetime; the higher the positive number, the more attractive the investment.
What is LCOE and why is it simplified here?
Levelized cost of energy is the cost per kWh over the system's life: LCOE = C_initial / (E_annual × n_life) + C_operating / E_annual. This is a non-discounted quick estimate; the formal standard definition discounts both costs and energy flows and should be used for official proposals.
Why can the payback period for street lighting look very long?
Street lighting projects save comparatively little electricity per luminaire, so pure financial payback is often unrealistic — evidence shows payback frequently exceeds 25-30 years. The real value of solar lighting is social and practical: no cabling, suitability for gridless sites, environmental benefit and low maintenance.
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