As people are now moving toward renewable energy sources. Power production through solar energy is becoming more common nowadays. As more and more solar farms are being developed, special arrangements for their management are also necessary. Statistics show that for an average industry, the installation and maintenance of a solar farm costs around $500,000 per acre. But still, the Solar capacity alone have risen to more than 26 times from the 2009 level — from 25 GW to an estimated 663 GW according to the United Nations Environment Programme (UNEP).
Solar farm inspections can generally be carried around by using either traditional methods or innovative aerial methods using drones. In the traditional way, there are essentially two methods for conducting inspections, one using hand-held devices while the other one involves using manned aircraft mounted with different sensors. PV technicians used to conduct inspections on trucks and foot rolls using handheld cameras. The project involves inspecting thousands of acres on foot and the time took almost weeks up-to a month. The other method involving manned aircraft was faster but expensive, with an estimated cost of around $1000 to $2000 per hour.
Therefore, drones are extensively used in the renewable energy industries. Drones make the work 10 times faster and 30-50% cheaper. We could realize the importance of drones from their aesthetic ability to take off and land from a specific point, travel long distances, and inspect a large area in just a couple of minutes. Drones provide managers of these solar farms with highly accurate data and help them identify faults in solar panels using thermal sensors and cameras.
Manual vs Aerial methods
To meet energy demands, solar farm companies need to set up a large area of land with solar panels. It is estimated that it requires around 2,500 acres of the solar farm to supply energy to around 100,000 households. To know more about it read from here Commercial Solar Farms & Large Solar Arrays. To ensure the smooth operation of these solar farms, it is necessary to inspect them routinely. Therefore, the management of such a vast area using traditional means is tedious and highly expensive. The traditional methods involve inspecting each solar panel using a hand-held device. The hand-held device contains thermal sensors and would show unusual heating of a certain panel in case of faults.
A 2015 EPRI study estimated that a cost of $10 to $25/ kW-yr is required for inspection and other preventive measures for solar farms. It even requires tremendous labor and tedious work, therefore stakeholders and companies move to aerial techniques and drones for more efficient and cheaper methods for solar farm inspection and management. Thermal imaging of solar panels using drones has reduced the cost and the labor required while the data collected through this technique is highly accurate. It uses different software and sensors. Solar panel inspection drones can inspect a large area and identify the solar panel problems while being in the air. Solar panels with faults or working with less efficiency show different temperature signatures. This out of the order temperature signature can be easily identified using a thermal camera attached to the drone.
Procedure for Aerial Solar Inspection using Drones
For performing and planning an aerial solar inspection using drones, the following five essential steps have to be undertaken:
1. Assessing the farm
The first step involves the inspection team to inspect the entire farm thoroughly. The complete dimension of the farm along with the number of panels installed and assess the capacity of power production. The inspection team needs to keep everything in mind before planning and beginning their aerial solar farm inspection.
2. Planning the Flight
The second step involves planning the flight. For this step, the inspection team needs mainly two basic pieces of information. The data collected during the first step while assessing the farm and secondly, the capacity of the pilots and the drones available. With these two important details, the aerial inspection team can plan the flights by calculating the ground distance points and the battery capacity of each drone. Flights are then planned and scheduled so it does not disrupt the workflow during the operations. To avoid any inconvenience, the inspection team must keep extra batteries and drones in case something goes out of order.
3. Collecting the Data
The most important part of aerial solar inspection drones is collecting the data. For this purpose, it uses high-resolution RGB and thermal cameras. An average drone can collect up to 260 high-resolution images per flight and can average up to 25 flights per day. It then converts the data collected during the inspection to thermal data output using different software.
4. Data processing
The ultimate step involves processing the data into a form that can be easily understood. For this purpose, Photogrammetry software constructs ortho mosaics and thermal maps from the images captured during the flight. It also adjusts the position of each point on the map using ground control points. After all the above steps are completed, it integrates the map files into a geography information system.
5. Reading the Data
After it completes the geographic information system, the maintenance team looks into the files and can easily and efficiently identify faults in the panels and repair them accordingly.
The Output from a Thermal Aerial Inspection
A thermal image from a solar plant represents the temperature output of the panels and each cell where the overheated area is known as a hotspot. Depending on the shape of the hotspot, one can deduce different results. Below, are some of these outputs:
1. Defective Cells and Substring
In the above figure, point 1 shows a defective substring, point 2 shows a defective individual cell, while point 3 shows the connection point. These deductions are based on the color and the shape of the hotspots.
2. Non-Functioning Panel
The above figure has a consistent light color that shows minimal heat in the panel thus indicating it to be non-functional.
3. Delamination on Two Cells
As we can see in the above figure that two blocks in the panel has an abnormal heat color map than the rest of the blocks. Hence it indicates delamination of two blocks i.e. cells in the panel.
4. Cell Rupture
A small bright heat color map can be seen in one of the blocks in the above figure. Therefore, it indicates that there is a rupture in one of the cells.
Statistical Analysis
According to this Forbes article, the world’s largest solar power plant is being developed in the United Arab Emirates. Since vast and major deserts are present in the UAE, along with the technological and innovative mind-set of UAE, these types of solar farms are best suited there. Therefore, the most advanced technological inspection system must also be present to handle such farms.
Drones for Aerial Solar Panel Inspection
Several drones can perform aerial solar inspections. However, DJI’s matrice 300 RTK drone equipped with Zenmuse H20 makes one of the best combinations. Multiple important factors make this drone and these integrated sensors a deadly combination.
First, the DJI Matrice 300 RTK has advanced AI capabilities. It has a flight time of up to 55 minutes and has high payload capacities. It also has 6-direction sensing and positioning, a transmission range of over 15 Km, and a primary flight display. Its integrated design helps to keep it stable, even in harsh weather. Therefore, in terms of solar farm inspection, it means that this drone can travel several kilometers for a longer period. Correspondingly, a greater number of images and data can be collected per flight.
On the other hand, the Zenmuse H20 is an integrated solution to several sensors used with a drone. It has a hybrid sensor that contains several sensors incorporated in it.
- 12 MP wide Camera
- 20 MP Zoom Camera (23x Hybrid Optical Zoom)
- Radiometric thermal Camera
- Laser Rangefinder
Therefore, it can easily provide a solution to the aerial inspection of solar plants since it contains both a high-resolution RGB camera and a thermal camera required to collect the important information regarding solar farm inspections.
GeoDrones
If you are looking for an effective way to get hold of this deadly combination, then visit https://geodrones.ae/#fleet that have a ready-to-use solution of drones for different purposes in aerial mapping and solar farm inspections.
You can also read about other uses of Drones in various industries like the Drones Bathymetric Survey.
Conclusion
Different techniques and processes are used by different solar farm management for inspecting solar farms in order to prevent any power disruptions. The traditional techniques of using hand-held devices are also used in many places, however, they have the disadvantage of being expensive and highly time consuming. The new culture of using unmanned aircraft, i.e. drones for solar farm inspection has reduced the cost of operation to 30 – 50% of using the traditional methods, and the process speed is increased up to 10-20 times. With progressing time, this method is becoming an essential element of almost every solar farm in existence due to its high efficiency and low functioning cost.
