Thermal Inspection of Solar Panels by Drone

Photovoltaic installations degrade silently. Cracked cells, defective bypass diodes, delamination, partial soiling — these anomalies go undetected by the naked eye yet directly weigh on production output, sometimes causing 10 to 30% generation losses. Drone-based thermal inspection maps an entire installation in a matter of hours, without dismounting a single module.

Why inspect solar panels by drone?

Ground-level or ladder-based inspections only allow examination of accessible modules, one by one. On a 500 kWp or larger installation, that means thousands of cells to check manually — a disproportionate task without the right tools.

A drone equipped with an infrared thermal camera surveys the entire installation systematically. The abnormal heat emitted by a failing cell — a hot spot — appears immediately on the thermal image, pinpointed to the exact module. Detection is fast, exhaustive and repeatable.

The other key advantage: no physical contact with the modules. No risk of scratching, crushing or damaging during the inspection. The drone flies, analyses, delivers.

Defects identified by thermography

Infrared thermography detects several categories of anomalies:

• Cell-level hot spots — localised overheating on one or more cells, often caused by partial shading, cracking or contamination
• Defective bypass diodes — the diode protecting a string of cells short-circuits permanently, generating overheating across an entire module section
• Delamination — partial separation of the encapsulant creating zones of elevated resistance and diffuse hot spots
• Differential soiling — dust, bird droppings or lichen creating selective shading
• Connection issues — poor contact at MC4 connectors, visible as overheating at junction boxes

Each anomaly is geolocated on a plant layout map, with its relative temperature differential and a prioritised action recommendation.

Optimal inspection conditions

The reliability of thermography depends on weather conditions at flight time. For actionable measurements:

• Irradiance above 600 W/m² — modules must be in a stable thermal regime for anomalies to be visible
• Wind below 4 m/s — wind dissipates heat and reduces the thermal differential between healthy and failing areas
• Stable ambient temperature — avoid transition hours (dawn, dusk) and intermittent cloud cover

In practice, optimal windows fall between 10:00 and 15:00 on clear days, from March to October at our latitudes.

Mission workflow

A thermal inspection of a solar installation runs in three phases:

1. Preparation — plant layout collection, automated flight plan design, regulatory checks (airspace, DGAC declarations)
2. Acquisition — systematic automated overflight with simultaneous visible and infrared capture for each zone
3. Processing and report — thermal image orthorectification, anomaly identification and classification, delivery of a mapped report with prioritised action list

Flight time is approximately 30 to 45 minutes for a 100 kWp installation. The report is delivered within 48 to 72 hours.

IEC 62446-3 standard

IEC 62446-3 defines requirements for thermographic inspection of photovoltaic systems. It specifies minimum irradiance conditions, anomaly classification protocols and expected report content.

Operators subject to maintenance obligations or whose installations are covered by performance guarantees (PPAs, O&M contracts) benefit from IEC 62446-3 compliant inspections to document asset condition for insurers and investors.

Our inspections follow the IEC 62446-3 framework, with structured reports meeting the requirements of insurers and asset managers.

Our field approach

We operate with the DJI Matrice 4TD, a professional drone combining a radiometric thermal camera and a high-resolution visible sensor on the same platform. This configuration enables precise overlay of thermal and visual imagery to locate each anomaly without ambiguity.

Our missions cover everything from small rooftop installations (residential or commercial) to multi-megawatt ground-mounted plants. Quotes provided on plan or following a preliminary site visit depending on complexity.