Why we scan solar panels with a drone

A solar panel converts sunlight into electricity. If that fails somewhere, that energy remains in the panel as heat. A defective panel is therefore literally warmer than its neighbors, and a thermal imaging camera captures that difference.

On a commercial roof with thousands of panels, measuring each panel individually is an impossible task. A drone maps the entire roof, including areas that are difficult or unsafe to access. We fly when there is sufficient sun and with the installation in operation, as only then do deviations become visible.

The software then overlays the thermal images onto the roof as one large map and marks every panel that deviates. This way, our technician knows exactly which panel to check beforehand.

What you see on the image

The image above is the heat map of a commercial roof of over two hectares. Purple is the normal state: panels that are working as they should and are all approximately the same temperature. The lighter the color, the warmer the surface.

The colored blocks are the deviations. Each block represents one panel that is warmer than it should be, and the color indicates the type of deviation. If many blocks are next to each other in a straight line, the cause usually lies not with the panels themselves but with the cabling or the connection behind them.

What the deviations mean

A scan distinguishes between five types. They differ greatly in impact: a hotspot costs you a small amount of yield from one panel, while an interrupted string shuts down an entire row of panels.

On this roof, the majority of the deviations were hotspots, but the greatest gain was found elsewhere: in the interrupted strings.

Not every deviation is a defect. For some hotspots, the cause is simply dirt or shade, in which case cleaning is sufficient. That is why we link a suspected cause to every deviation.

What happens after the scan