Do you have an unusual or complex solar site that needs an inspection, but aren’t sure it is possible? Maybe it is a floating site or you have thin-film panels, can you still get a drone inspection and capture accurate aerial data for analysis and reporting? Check out some of the unique surveys that Sitemark has performed and discover if we can help with your particular site as well.
Solar Site Types
Ground based: While ground based panels may seem the most clear cut and simple of solar installations, they too can have issues with inspection. For example, given the amount of land space they consume they are often used in remote or hard to access areas. These areas may also exist in harsh conditions such as in the desert or mountains. Also, in such areas where land is usually less costly and less populated, they can be ideal for very large solar sites. These sites can be so large that they are impossible to check manually, i.e. by the time an inspection is completed, the next inspection will be required. All of these situations make them ideal for drone inspections.
Roof based: Popular in urban areas and an excellent use of unfeasible space, rooftop installations have ample benefits. However, one of their cons is the difficulty of access and therefore, inspection. This location also presents a concern for the safety of inspection personnel. All of these issues are resolved with a drone inspection. While there can be more restrictions in urban areas for flying drones, Sitemark assists by providing an approved drone operator if needed. In addition to the solar panels, the drone inspection also identifies other problems rooftop concerns such as thermal leakage.
Floating: These are the same PV panels as those used for traditional terrestrial systems that float on water bodies allowing solar power to be generated by the solar irradiance that would otherwise strike bodies of water. One of the most beneficial aspects comes from placing them on bodies of water that were previously unused or even unusable. These are the aquatic equivalent of brownfields: water that is man-made (meaning ecosystem disruption is less), inland and calm. But the downside is that any installation, maintenance, and inspection to solar panels have added costs and complexities when they must be performed on the water. Since you can’t walk alongside the panels for a hand-held, manual inspection, here again a drone inspection is truly the best, if not only, practical inspection option.
Single–axis trackers: A single-axis tracker moves the panels on one axis of movement, usually aligned with north and south. This type of system is designed to maximize solar energy collection throughout the year. Single-axis trackers are the most common tracking systems installed today. Although dual-axis trackers can increase total energy production by 5-10% above a single-axis tracker, single-axis trackers are more cost-effective and reliable. But while they are superior for PV productivity, they are indeed tricky to inspect. The complexity lies in the fact that the panels move. This poses operational issues at the time of flying: the orientation of the trackers has to be taken into account by the pilot. At Sitemark, we have very clear guidelines for the pilots to ensure the data acquisition process is smooth and to help tackle the complexity.
Dual–axis trackers: A dual-axis tracker allows your panels to move on two axes, aligned along both the vertical axis and horizontal axis. This type of system is designed to maximize your solar energy collection throughout the year. It can track seasonal variations in the height of the sun in addition to normal daily motion. As with the single-axis, the intricacy of the inspection is due to the moving panels and complex geometric structure, both of which are a challenge for traditional photogrammetry-based drone solutions. At Sitemark we have developed a unique process to deliver a very high quality orthomosaic of your double axis site, allowing you to benefit from a large view of your site and verify the analytics we deliver.
Solar Panel Technologies:
Mono/ Polycristaline: Both monocrystalline and polycrystalline solar panels have cells made of silicon wafers. Monocrystalline solar cells are more efficient because they are cut from a single source of silicon. Polycrystalline solar cells are blended from multiple silicon sources and are slightly less efficient. These are the most common type of panel structure and do not present any unusual difficulties for inspection
Thin–film: Thin-film solar panels are made with solar cells that have light-absorbing layers about 350 times smaller than that of a standard silicon panel. Because of their narrow design and the efficient semi-conductor built into their cells, thin-film solar cells are the lightest PV cell available while still maintaining strong durability. Efficiency has been the ultimate deciding factor that has prevented thin-film panels from gaining a foothold in the residential PV market. Whereas today’s standard silicon PV panels will have somewhere in the range of 15-20% efficiency, thin-film panels will likely hold a median closer to 11-13%, which can significantly impact your system’s physical size and electricity output. Thin film needs to be installed on larger areas to accommodate the increased amount of space necessary for the system. For inspection purposes, these types of panels do not provide any particular inspection obstacles except that less types of anomalies can appear.
Bifacial: A bifacial solar panel is double-sided. These panels absorb sunlight from the front and rear sides via a transparent back sheet. The challenge with bifacial has always been the unpredictability of the power output because it’s dependent upon the substrate behind the modules, e.g. a white commercial roof, a dark comp shingle, grass, gravel, etc. Therefore, it is hard to model what the module is going to produce. For inspection purposes, it is not possible to inspect the underside of a panel, only the front that is exposed to the drone camera’s view.
Split-cell: Split cell technology is a new cell architecture that increases voltage by halving the size of the silicon chips. By cutting the standard cell in half and bus-barring it, they have the advantage of increasing efficiency, lowering voltage and lowering the operating temperature. These last two benefits increase module longevity through decades of thermal cycling, eliminating hot spots. Also, split cell panels are stronger than traditional modules.
You have many options available to you as a solar site stakeholder, and we understand your primary goal is to maximize productivity no matter what your choice of solar panel technology or site location. Keep in mind that Sitemark’s Fuse platform is highly flexible and supports all of the variables discussed above. But even if your unusual panel or site is not listed here, please contact us with your questions or for advice as we love a challenge 😀.