Are heat maps simply a powerful visual plant visualization tool or do they serve more purpose? Are they a “nice to have” or are they essential for correct thermography? Why are they more expensive than conventional thermography?
Solardrone has recently transitioned to offering its customers thermal + RGB maps, and this post explains why this transition occurred:
Each flight in a photovoltaic plant generates more than 6,000 images/MWp. Thousands of disconnected images that are manually reviewed to detect, locate and classify each module with anomalies. The flights generate image sequences of this type:
It is relatively obvious to detect an anomaly within these images but, when we are in fixed plants or 1-axis tracker plants, the following very often happens: we have detected a thermal anomaly within an immense sea of modules without any visual reference. And the GPS coordinates of the aircraft are not enough to know in which column said module is located exactly:
Location problem in fixed plants and 1-axis trackers.
The only option in these cases is to manually count, photo by photo within the captured image sequence, until we know in which column the module with anomaly is located.
This arduous counting process, being manual, generates a multitude of errors. Approximately 1 in 20 modules are located incorrectly following this method currently widely used in the industry.
Locating a module correctly or ensuring its traceability should not be a “nice to have” but a “must to have”.
Stitching images (thermal maps) allows us to solve this problem. The thermal map (3 cm/pixel) + RGB (< 1 cm/pixel) is the only solution to ensure that all fixed plant modules and with 1-axis trackers have been thermographed and located correctly.
This is easier said than done. Thermal maps bring a great technical challenge and require a large amount of extra time during flights carried out in the field (up to triple the time). This increases costs and operational complexity, as well as limiting resolution to 5 cm/pixel.
Solardrone has invested a large amount of resources in R&D to achieve the most optimal solution: instead of mapping the entire plant area, including soil, only a linear stitching of the photovoltaic panels is carried out, so that it is optimized flight time enormously, achieving identical times as if a thermal map were not being carried out. It is the perfect balance between having the best technical solution and the best cost.
As a summary, the following table clarifies the advantages of working with a thermal map and confirms that it is the correct way to follow when carrying out aerial thermography in photovoltaic parks: