Soria, Spain – December 24th 2015

The repeated economic cut backs suffered by renewable energy sources in Southern countries of Europe have pushed traditional operators to significantly reduce maintenance cost on their photovoltaic assets without compromising the quality of the asset. Apart from the financial factors, the oldest sites are reaching the barrier of the ten years continuous operation, therefore, modules, inverters and trackers are experiencing their design end-of-life failure.

Since the resources are limited and keeping in mind that labor costs are one of the mayor budget points, O&M service providers shall invest on technology that increases their efficiency and competitiveness. The use of drones to get aerial thermal images is one of the tools that enhance the photovoltaic modules’ inspection. Here you will find some facts that you should know before getting your hands on this trendy gadget.



After five years carrying out thermal inspections on photovoltaic modules with different teams, technologies and at different locations; we realized that only a multi-skilled team will yield the best results. Here is summary of what key activities shall be considered.

  • Drone1Pilot and drone owner: The drones used for thermal inspections are multi-rotor heavy duty drones with 10 to 15 min autonomy that only a few people in each country/state owns a flying license for, the maintenance of the drone and the associated insurances should also be taken into account.
  • Thermal analysis expert: When solar cells are inspected from the front, a thermal imaging camera can see the heat distribution on the glass surface but can only see indirectly the heat distribution in the underlying cells. On top of that the reflectance of the glass has a severe impact on the quality of the image. A thermal analysis expert will look for the appropriate angle, distance and fly speed to optimize the time and enhance the results.
  • PV Modules expert: This is actually the most valuable activity, since thermal images only provides you malfunction evidence, but only an experienced photovoltaic expert, in other words, a “PV Doctor“, will lead to an accurate diagnosis and a cost-effective resolution case by case.

The above mentioned services are rarely ever provided by just one company. Typically the last player leads the process, receives the raw data and elaborate a report to the end user.



  • Drones will help you when further decision has to be taken. A multi-MW site might be affected from severe PV malfunctions. Therefore, before investing on an accurate thermal inspection, a drone thermal inspection with a limited budget can trigger a Multi-€ decision.
  • Drones will help you when contractually you are forced to make an inspection but the client just wants to track the evolution of the PV plant and no corrective measures will be taken.
  • Drones will help you when it exists a physical limitation to run a 5º-60º thermal inspection by hand. For example front inspection on PV modules mounted on dual-axis trackers (ie: Spain, Italy), rooftops with additional hazards, or PV modules with very low tilt angles (ie: Japan).
  • Drones will help you in those places where 500W-700W/m2 together with a day with a clear sky are uncommon (ie: United Kingdom).



  • Drones won’t help if the size of the site is very small, a minimum size of 3-5MW is required to justify a deployment of experts.
  • Drones won’t help you to claim a warranty. PV Module manufacturers require a dedicated report with both front and back pictures and thermal image, reference number and additional administrative support.

In conclusion, the thermographic inspection of photovoltaic systems with drones allows the fast localization of potential defects at the cell and module level but a good assessment of the PV plant will only be carried out by expert PV players that will guide you through the most cost-effective solution to your PV asset.


About Solarig.

SOLARIG is a global solar photovoltaic integrator with over 10 years of experience and more than 350MW utility scale and commercial PV sites in operation. SOLARIG is an active player in development, engineering and asset operation and maintenance spread out over more than 3 continents with solid infrastructure in key markets (Japan, UK, France, India, Spain and Italy). We tailor our services to turn our clients and partners ideas into action through Flexibility, Transparency & Competitiveness.

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