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Solar Capacity Factor Calculator

Calculate the capacity factor of a solar installation and compare it with other sources.

About Solar Capacity Factor Calculator

Solar capacity factors run from about 10 per cent in cloudy northern climates to 25 per cent in sunny ones, against 40 to 50 per cent for wind and over 90 for nuclear. The figure reflects resource availability rather than equipment quality. Capacity factor is what makes generation capacity figures misleading: a gigawatt of solar produces far less annual energy than a gigawatt of baseload plant.

Formula

Solar Capacity Factor

Capacity factor = actual generation ÷ (capacity × 8,760 hours)

capacity factor
Share of theoretical maximum output actually achieved
full-load hours
Hours at full rated output that would give the same energy

Worked example

With the default values below, Solar Capacity Factor Calculator returns Capacity Factor of 14.840%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Annual generationminimum 0 kWh
6,500 kWh
Installed capacityminimum 0.001 kW
5 kW

Results

Capacity Factor
14.840%
Equivalent Full-Load Hours
1,300.0 h
Specific Yield
1,300.0 kWh/kW
Theoretical Maximum Generation
43,800 kWh
Comparison
Below average — check shading and orientation

Step by step

  1. 1Values used
  2. 2Solar Capacity Factor
  3. 3Capacity Factor= 14.840
  4. 4Equivalent Full-Load Hours= 1,300.0 h
  5. 5Specific Yield= 1,300.0 kWh/kW
  6. 6Theoretical Maximum Generation= 43,800 kWh
  7. 7Comparison= Below average — check shading and orientation

Assumptions and limits

  • The result is derived only from the 2 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

How is Solar Capacity Factor calculated?

Capacity factor = actual generation ÷ (capacity × 8,760 hours) Solar capacity factors run from about 10 per cent in cloudy northern climates to 25 per cent in sunny ones, against 40 to 50 per cent for wind and over 90 for nuclear. The figure reflects resource availability rather than equipment quality.

Why does Solar Capacity Factor matter?

Capacity factor is what makes generation capacity figures misleading: a gigawatt of solar produces far less annual energy than a gigawatt of baseload plant.

What values do I need to enter?

This calculator takes 2 inputs: Annual generation, Installed capacity. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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