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How much will your plant produce, month by month?

A city or a pair of coordinates, the orientation, the tilt, the peak power. The calculation reconstructs the path of the sun on a typical day of each month, projects the irradiation onto the plane of your modules, then applies the efficiency loss due to temperature.

Estimated annual production —kWh / year
Specific yield —kWh / kWp / year
Performance ratio —%

MonthIrradiation in the plane of the modulesProduction

The assumptions behind the calculation

They are written here because a yield without its assumptions means nothing. On a study, each one is taken again from your site and your equipment.

    What this calculation is not

    • It ignores shading: a neighbouring building, a parapet, a tree, a row of modules shading the next one. On a cluttered roof the difference runs into tens of per cent.
    • It assumes a single plane. A roof with several pitches is calculated pitch by pitch.
    • For a tracker, backtracking is accounted for but not the lie of the land, nor the losses of a misaligned axis or of a row at the edge of the field.
    • It works on a mean day per month, not on an hourly year. It gives a reliable annual order of magnitude, not a profile you can size storage from.
    • It describes an average year. A real year departs from it, and a bank will ask for a P90, which only a long series can establish.
    • It says nothing about how much of this production you will consume . That is what the load curve is about, and that is where the economics are decided.

    A figure to confirm before you commit a budget?

    We take this calculation onto your real site: shading surveyed, module layout, equipment chosen, and a comparison against your load curve.

    An engineer calls you back for a scoping conversation, with no commitment.

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