Calculate payback period and levelised cost of electricity of a PV system from investment, operating cost, degradation, self-consumption and feed-in.
LCOE means levelized cost of energy: discounted lifetime cost divided by discounted lifetime electricity generation.
Complete the inputs and calculate.
Compare investment and operating cost with avoided imports and export revenue.
Investment, lifetime, maintenance, degradation, discount rate, self-consumption, import and export tariffs.
LCOE responds to discount rate, lifetime and degradation, while simple payback ignores time value. Self-consumption is often more valuable than export because it avoids a higher retail price.
LCOE (levelized cost of energy) = discounted lifetime cost / discounted lifetime generation. Simple payback divides investment by annual value.
With €18,000 investment and €1,200 annual value, simple payback is 15 years; degradation and replacements can raise LCOE.
Sources and limits: Discounted energy economics; include financing, taxes, inverter replacement and tariff changes only as explicit inputs.
Compare investment and operating cost with avoided imports and export revenue.
Energy calculators balance quantities over time and separate useful energy, losses and grid import. This matters because power is instantaneous while energy is its time integral.
LCOE (levelized cost of energy) = discounted lifetime cost / discounted lifetime generation. Simple payback divides investment by annual value.
Investment, lifetime, maintenance, degradation, discount rate, self-consumption, import and export tariffs. LCOE responds to discount rate, lifetime and degradation, while simple payback ignores time value. Self-consumption is often more valuable than export because it avoids a higher retail price.
Enter investment, expected lifetime, annual maintenance cost, degradation, discount rate, self-consumption share and electricity import/export tariffs. The calculator returns both simple payback time and the discounted LCOE.
With €18,000 investment and €1,200 annual value, simple payback is 15 years; degradation and replacements can raise LCOE.
LCOE responds to discount rate, lifetime and degradation, while simple payback ignores time value. Self-consumption is often more valuable than export because it avoids a higher retail price. An annual value describes a scenario, not a guarantee for every day. Efficiency, coincidence, temperature, driving profile and tariff assumptions can change practical results more than rounding.
Investment and running cost in euros, lifetime in years, tariffs in €/kWh, LCOE in €/kWh.
Comparing the economics of different PV investments or financing assumptions, or assessing how much a changed self-consumption share affects payback time.
Discounted energy economics; include financing, taxes, inverter replacement and tariff changes only as explicit inputs.
Common mistake: Don't treat simple payback and LCOE as the same metric – simple payback ignores time value, degradation and discounting, while LCOE explicitly prices these in and is therefore more meaningful for a lifecycle comparison. Don't value all generation at the full electricity price if part is actually exported; self-consumption and export have different economic value.
Simple payback uses one annual value with no discounting; LCOE spreads discounted cost over discounted generation across the whole lifetime, accounting for degradation and the time value of money.
Avoided grid import typically saves the full retail electricity price including taxes and levies, while the feed-in tariff is usually noticeably lower.
A higher discount rate weights future output less, raising LCOE; simple payback time is unaffected since it uses no discounting.
LCOE includes investment, maintenance, degradation and discount rate. Simple payback compares investment with annual value from avoided imports and exports.
Financing, taxes, inverter replacement and tariff changes must be represented with explicit inputs or scenarios.
Inputs, units and assumptions remain traceable in the result. Planning and approval require measured data, manufacturer documentation and a time-series simulation.