Eleven solar plants, 33,333 panels: our panel-by-panel thermal diagnosis
Between 17 June and 17 September 2026 we carried out thermal surveys of eleven photovoltaic plants for Genergies, which operates and maintains them: two in Martinique, in Le Carbet and Bellefontaine; eight ground-mounted plants in Guadeloupe, in Le Moule, Petit-Canal, Saint-François and Gourbeyre; and one installation spread over the roofs of three commercial buildings in Matoury, French Guiana. In all, 33,333 panels were checked one by one.
Before the flight
For Bellefontaine and the eight Guadeloupe plants, the operator sent us its layout plans showing the modules in service. On several Guadeloupe plants, areas of out-of-service modules had been isolated: we outlined them on our maps without counting them as defects. Then come the prevention plans signed with the operator and, in populated areas, the prior flight declaration; in Matoury, a site open to the public, we also asked for an on-site contact in case of inspection. One last condition: the plant must be producing, because without current the defects do not heat up.
The flight sequence
On each plant, the flights generally follow the same order: a quick flight to produce a surface model, which then lets the drone follow the terrain; a visible-light flight at 1 to 1.5 cm per pixel; then the infrared flight, with a 640 × 512 radiometric camera, at 2.8 to 4 cm per pixel depending on the height the site imposes. Images are geotagged with RTK. Irradiance ranged from 720 W/m² in Matoury in September to 1,267 W/m² in Petit-Canal in August: always above the 600 W/m² threshold set by the IEC TS 62446-3 standard, below which temperature differences become too small to be read reliably.
One record per panel
Back at the office, the infrared images are converted into temperatures, then assembled into georeferenced visible and infrared orthophotos. Each table of panels is drawn on the orthophoto and divided into panels, and each panel receives an identifier giving its table and position (B79 2-4, for example). An operator then classifies every anomaly: single hot spot, cluster of hot spots, module defect, faulty bypass diode, cut string, shading by vegetation, shadows or soiling, or ‘other’, with a comment (possible soiling, condensation, impact or crack) calling for a check on site. A second operator reviews the whole before the report is approved.
The detailed report devotes one page to each flagged panel: infrared and visible thumbnails, minimum, mean and maximum temperatures, GPS position and a directions link, so that the maintenance team can go straight to the panel. It comes with a one-page summary giving the plant’s operational level, a multi-layer defect plan and the orthophotos, in RGAF09 / UTM 20N in the French Caribbean and RGFG95 / UTM 22N in French Guiana. The same data can be viewed in the Sentinel Cloud thermography module.
From report to maintenance
The type of defect determines the response: a module defect leads to replacing the panel, a cut string to an electrical check, shading by vegetation to mowing or clearing. On the map, the layout of the defects can be read at a glance, for instance when several module defects follow one another along the same column of a table.
For the operator, each report becomes a work list (panels to replace, strings to check, rows to clear) with the exact position of each item. The eleven reports were delivered between 18 June and 21 September 2026.
