CASE C39 · IN · 2021
55 MW solar field in Tamil Nadu, India: thermal drone survey flags 2,481 of about 233,000 panels
A research team flew a thermal drone over a 55 MW solar field in South India and flagged 2,481 suspect panels out of about 233,000. An orthomosaic served as a digital twin for locating them. Irradiance was not measured and the claimed 97% accuracy is not supported by figures in the text.
| Owner | Not named (site survey supported by Watsun Infrabuild Pvt. Ltd.) |
| Provider | NIT Karnataka (Surathkal) with the National Observatory of Athens (research team) |
| Location | Moongiltholuvu, Tamil Nadu, India |
| Aircraft | Not specified (multirotor with thermal camera, flown at 130–140 ft) |
| Sensors | thermal infrared, RGB for orthomosaic |
Before
Checking panels one by one from the ground is impractical at this scale; high aerosol loads, dust and monsoon weather accelerate soiling and degradation.
With drones
Sixteen flight paths flown in February 2021; an orthomosaic built in open-source WebODM served as a digital twin, and hotspots were marked in QGIS and compared with ground measurements.
Outcomes
| Metric | Value | Basis |
|---|---|---|
| panels mapped | 232,934 panels identified across six blocks (5 × 10 MW, 1 × 5 MW) | Reported |
| defects flagged | 2,481 panels (about 1.1%) indicated as defective (hotspots from manufacturing faults, ageing, shading, soiling, hail) | Reported |
| accuracy | "up to 97%" stated in conclusions; underlying validation numbers not shown | Company claim |
Caveats & limits
- Single-site academic study; the plant owner is not named and drone/camera models are not given.
- The abstract says defects were indicated automatically, but the methods describe manual marking; the 97% accuracy figure is not traceable in the text.
- Irradiance was not measured during the flights, although thermography guidance (about 500–700 W/m²) depends on it. The authors cite a lack of thermographic know-how as a main limitation.
Sources
- Solar Photovoltaic Hotspot Inspection Using Unmanned Aerial Vehicle Thermal Images at a Solar Field in South India (Remote Sensing 15(7):1914)MDPI Remote Sensing Full text read
Sources checked: 2026-10-22