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Solar Farm Output Calculator

Work out solar farm output instantly with clear inputs, formula shown and shareable results.

About Solar Farm Output Calculator

Specific yield in kilowatt-hours per kilowatt-peak per year already embeds irradiance and system losses, so annual generation is capacity times specific yield. Modules degrade at 0.3-0.7% a year, so lifetime generation is a geometric series over the project life rather than 25 times year one.

Formulas

Annual generation

Generation (MWh) = capacity (MWp) x specific yield (kWh/kWp)

Degradation

Year n = year 1 x (1 - degradation)^(n-1); lifetime = year 1 x (1 - (1-d)^n) / d

Worked example

With the default values below, Solar Farm Output Calculator returns First Year Generation of 77,500.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Installed Capacityminimum 0 MWp
50 MWp
Specific Yieldminimum 0 kWh/kWp/year
1,550 kWh/kWp/year
Performance Ratioaccepts 1–100 %
80 %
Annual Degradationaccepts 0–5 %
0.5 %

Results

First Year Generation
77,500.0
Year 25 Generation
68,715.6
25-Year Lifetime Generation
1,825,586
Capacity Factor
17.694%

Step by step

  1. 1Values used
  2. 2Annual generation
  3. 3Degradation
  4. 4First Year Generation= 77,500.0
  5. 5Year 25 Generation= 68,715.6
  6. 625-Year Lifetime Generation= 1,825,586
  7. 7Capacity Factor= 17.694

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or fees or charges into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is the difference between specific yield and performance ratio?

Performance ratio is the fraction of theoretical output actually delivered, capturing temperature, soiling, inverter and wiring losses. Specific yield is the resulting energy per unit capacity, which already includes it.

What performance ratio is achievable?

78-84% for a well-designed utility plant in a temperate climate, lower in very hot climates where module temperature losses are larger.

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