Drone Surveying and Inspection for Renewables: Lower Costs, Faster Results, and Better Data

     Unmanned aerial vehicles (UAVs), or drones, are used in many industries and are particularly applicable to industries that are spread out through land space, air space, or ocean space. The utility industry uses drones for the inspection of power lines and facilities. The oil and gas industry uses drones to detect methane leaks along pipelines. Agriculture uses drones to assess crop health and issues. Drones can inspect to detect issues at large construction or energy projects. They can be used to collect data over large areas and in remote areas. Drone applications overlap with robotics and AI applications. Robots clean solar panels in dry climates where dust is a common problem. Robots and AI can pick fruit, apply fertilizer, and water plants with precision and speed.

     Many small innovations over the past several years have made the deployment of utility-scale solar projects more efficient, bringing costs down. Here I will be focusing on cost-savings drones and technologies carried by these drones.

     Engineering firms can help drive down costs by applying and combining new technologies. One place this can happen is on the front end of renewable energy projects, at the surveying stage. Before a utility-scale solar and wind farm begins construction, surveyors create high-quality maps that developers then use to plan the layouts of their facilities. Creating an industry-standard American Land Title Association (ALTA) survey typically involves conventional surveying to identify boundaries, utilities, and easements. It may also involve photogrammetry and light detection and ranging (LiDAR) sensors to map topographic and planimetric features. In recent times the use of drones to carry and conduct LiDAR surveys along with GPS technology has sped up the surveying process while also making it more accurate, particularly with respect to topographic and planimetric information.

     Just in the last few years, some past problems with LiDAR conveyed via drones have been worked out so that this can now be done with a higher degree of precision. The problems involved designing smaller sensors that were just as accurate as larger ones used on manned aircraft. Another issue that was worked out involved “trajectory files that depend on GNSS measurements and the Internal Measurement Unit (IMU), which records the roll, pitch, and yaw of the aircraft’s sensors,..” This allows for more precision in mapping. Other improvements over the last few years include higher-resolution cameras, longer battery life, and lighter payloads. More satellites now feed into global navigation systems. These all improve accuracy and speed and lower cost. Drones can also conduct surveys in an automated fashion programmed by the surveyor, with a pilot around mainly to avoid crashes. With these microdrones, surveys can be done in a fraction of the time and at a fraction of the cost compared to the past.  A company called Microdrones began offering surveying and LiDAR in a microdrones-as-as-service format in 2020. They offer a monthly subscription service that can offer cost savings for many customers. They have different data processing and post-processing that can be selected by the customer based on the needs of the project. Engineering firms are also buying drone fleets to add drone surveying to their repertoire. Solar companies can also bring drone surveying in-house.

     Drones can also be used to monitor renewable energy systems to detect issues. They can survey regions to collect wind data or solar radiation data. They can be used to detect and evaluate issues with wind turbines to reduce worker time and risk. They can also help workers design better repairs. Drones can monitor and detect solar panel malfunctions at big solar farms, also reducing worker on-site time requirements. Some drones can even be powered or partially powered by solar and wind. Drone-enabled technologies can reduce O&M costs and improve O&M significantly. The area around solar panels can get very hot, especially in desert areas. The drones and their payloads need to be built to withstand these temperatures.

Source: Incorporating Drones: Solar Energy Operations. (Webinar) DJI. Measure. AES. web player (djivideos.com)

Source: Incorporating Drones: Solar Energy Operations. (Webinar) DJI. Measure. AES. web player (djivideos.com)

     Drones can streamline solar farm inspection by quickly identifying defective panels and cables. This is much more efficient than using people with handheld thermal imagers. According to DJI Enterprise inspecting solar farms involves four basic steps: assessment, flight planning, data collection, and data organization and processing. Flight planning involves optimizing battery power. Data processing involves using photogrammetry software to reconstruct RGB color data (orthomosaics) and thermal maps and adjustment of positioning with Ground Control Points. The data can then be fed into GIS software. Then the maintenance team can look for anomalies that indicate potential faults. Aerial images can be interpreted to assess panel health. Heat anomalies across cells, strings, or panels can be caused by multiple issues such as “delamination, cracks, dust, or internal issues such as the inability to connect to a panel due to an inverter or cable failure.” One drone inspector noted that with two drone teams, they could inspect 617 acres in a single day compared to three or four months to do it manually. This makes inspection incredibly efficient and reduces human error. Early detection of faults can prevent major system failures and ensure output. While thermal imaging can lead to fault detection, RTK modules can lead to precision mapping at the centimeter level. Both of these technologies can be very efficient and very effective when carried by drones.

     The graphic below shows the full scale of potential drone-enabled applications for utility-scale solar farms.

 

Source: Incorporating Drones: Solar Energy Operations. (Webinar) DJI. Measure. AES. web player (djivideos.com)

References:

Surveying technology moving the needle for solar PV deployment. July 31, 2023. Solar Builder Magazine. Technology moving the needle for solar PV deployment (solarbuildermag.com)

Drone Usage for Renewable Energy Development and Maintenance. Jane Marsh. September 30, 2022. Bioenergy Consult. Drone Usage for Renewable Energy Development and Maintenance (bioenergyconsult.com)

Need laser-focused C&I solar design? Time to check out LIDAR. Builder Magazine. July 17, 2023. Need laser-focused C&I solar design? Time to check out LIDAR | Solar Builder (solarbuildermag.com)

Microdrones as a service? Professional drone LiDAR and surveying more accessible than ever. Chris Crowell. Solar Builder. May 19, 2020. Microdrones as a service? Professional drone LiDAR and surveying more accessible than ever | Solar Builder (solarbuildermag.com)

Everything Yoe Need to Know About Drones for Your Solar Farm. DJI Enterprise. Everything You Need to Know about Drones for Your Solar Farm (dji.com)

Incorporating Drones: Solar Energy Operations. (Webinar) DJI. Measure. AES. web player (djivideos.com)