Raptor Maps recently released a case study that reports on five heavily impacted sites owned and managed by a large, U.S.-based asset owner. The owner’s solar portfolio totals more than 410 MW of PV assets across the United States. This case study analyzes five PV systems of over 280 MWs, ranging in size from 1 to 200 MWs, and site locations distributed across the U.S. The data capture (aerial inspection) and analysis (data processing and deliverables) was performed via a mixture of internal drone operations by the O&M subcontractor and turnkey aerial services delivered via Raptor Maps. The article below is an overview of each PV system covered in much greater detail in the full Portfolio Case Study.

0.86MW Rooftop Solar PV System in New Jersey

This rooftop PV system was inspected for the asset owner by Raptor Maps’ local turnkey services. The inspection took one hour to complete including set up, flight, and demobilization. This inspection uncovered 4 hot cells, 6 cracked modules, and 1 offline inverter. These anomalies were impacting more than 5% of the site’s production capacity and estimated to result in $1,800 of annual revenue loss if not addressed. Performing the rooftop inspection via aerial thermography prevented any inspection related injuries and greatly minimized the amount of time required by the field technicians to be onsite for their inspection and repairs. The O&M subcontractor utilized Raptor Maps’ platform and the detailed anomalies map to quickly identify the modules and inverter requiring a further look and send the exact number of repairmen and supplies to remediate all issues.

6 MW Ground Mount DG Solar PV System in Minnesota

This 6 MW PV system was inspected as part of the annual preventative maintenance scope of work using Raptor Maps turnkey services and local, professional, and experienced drone pilots. The inspection uncovered 490 anomalies, categorized into 16 anomaly types, and amounting to 2,853 affected modules. Instances of shading due to the tree line was one of a few major issues identified by the drone inspection, impacting the performance of more than 2,200 modules. Equipped with this data, the O&M team was able to quickly and accurately create a detailed plan to resolve all major PV system anomalies causing performance issues and impacting revenue.

RGB Imagery of shading impacting the PV system

13 MW DG Solar PV System in South Carolina

This site was inspected by the O&M subcontractor responsible for operating and maintaining this plant. The O&M team had built an internal drone program in 2019. They found the large amounts of data generated by the drone inspection difficult to analyze and organize and began using the Raptor Maps data-processing and reporting platform shortly after launching their drone program. Using Raptor Maps’ Flight Guidelines and Data Requirements, the O&M’s internal pilot managed all data capture (flights) and uploaded the imagery for automated data processing and report generation. The thermal drone inspection and reports uncovered 1,826 anomalies, across 9 categories, totaling more than 2,300 affected modules. The final reports identified and localized 10 malfunctioning strings, 379 diode faults, and over 400 cases of vegetation problems across the northwest side. The detailed reports and HD color imagery (RGB) enabled the O&M team to effectively assess all 400 cases of vegetation and is now utilizing Raptor Maps flight guidelines and data processing software to perform regular aerial inspections to maintain optimal site conditions.

RGB Imagery of some of the cases of vegetation that impacted the PV system’s production.

79 MW Utility-Scale Solar PV System in Arizona

The O&M subcontractor managing this utility-scale plant, as well as other large solar assets in the region, had a very tight timeline to complete all aerial thermography inspections before their site visits. Though this O&M subcontractor had an established internal drone program, they outsourced the aerial inspection to Raptor Maps’ turnkey services to free up their labor resources for other needed activities. By utilizing our turnkey services, we handled the aerial inspection, data analysis, and delivered them a report, allowing the O&M subcontractor to focus on other sites they managed. Upon inspection completion, the report identified 50 inverter faults, resulting in over 4% of annual production loss if left unrepaired. The O&M team knew that the site was facing inverter issues due to internal monitoring signals, but the exact number and locations were unclear. The O&M team prioritized their time onsite to resolve the numerous malfunctioning inverters and were able to reduce labor costs by deploying only the necessary number of technicians and resources to resolve all major issues.

199 MW Large Utility-Scale Solar PV System in California

This utility-scale PV system’s O&M vendor was alerted by their system monitoring software that the site was significantly underperforming in various blocks. Due to the large size of the site–more than 1000 acres– and difficulty in locating the string and module-level faults using field walks and IV-Curve tracing would be too expensive. In addition to the costs of these methods in both time and labor resources, they decided to use the faster and cheaper drone inspection option. The O&M subcontractor consulted with Raptor Maps regarding what level of aerial inspection would be appropriate for this investigative inspection and chose a two-phase inspection. The first aerial PV inspection would be a high-level, Raptor Overview level inspection to quickly identify and localize major issues impacting performance as well as heavy concentrations of lower priority faults. After the completion of the first phase, the second deployment would be a Raptor Comprehensive level inspection, targeting heavily impacted areas of the site to collect more detailed analytics on the anomalies causing the performance issues. The report identified thousands of performance issues across 6 categories, totaling 3,114 anomalies. There were almost 20,000 impacted modules resulting in over 7 MW of production lost and almost $300,000 of annual revenue loss if left unresolved for the next 12 months. The O&M team utilized Raptor Maps interactive map and a printed out copy of both the .PDF and Excel spreadsheet reports to create a detailed remediation plan. The site manager was able to deploy their team to every anomaly without wasting time locating the box or module. The team was able to resolve all major issues impacting system performance within a few weeks and return the PV system to optimum production levels.

RGB Imagery of tracker issues discovered in the aerial inspection.

In Conclusion

The client added Raptor Maps’ turnkey services and to support their O&M subcontractors in early 2019. Within nine months, over 340 MW of sites were flown, analyzed, and reported on. They utilized the versatility of aerial thermography and data analysis through both turnkey services and software. In addition, the asset owner decided to add their O&M subcontractors that self-perform drone inspections to their Raptor Maps account. This enabled the O&M subcontractors to upload, analyze, review, share, and host their drone inspection imagery in a central place and access it as needed.

Download the full case study here!

Using Drones and Software to Support Warranty Inspections

Aerial PV system inspections can be used for a variety of applications and reasons. The purpose of this blog post is to discuss the benefits of using drones and Raptor Maps for the inspections of sites for warranty reasons. Regular inspections of a PV system are a common part of asset management and O&M and need to be done regularly to maintain the validity of the warranty. Regular inspections also create data sets and reference points for future inspections, helping you identify the time period in which the problem started. 

In our experience across more than 25GW of PV inspections, there are 3 common options used for PV system inspections. Option A, Human labor consisting of field walks and visually identifying warrantable issues, option B, manned aircraft (airplane) inspection of a PV system, or option C, the use of drone technology to perform the inspection. Unless your solar PV system is extremely small and can be thoroughly walked and visually checked in a couple of hours, we have found that using a drone is the most efficient, cheapest, and quickest method. The capabilities of even an entry-level industrial drone reduce the inspection process time, and the amount of time it takes until you receive your report.  

With I-V curve tracing, PV system inspections require:

1 MWp = Multiple days

100 MWp = Multiple Weeks

With a thermal drone, PV system inspections require:

1 MWp = Less than 1 hour

100 MWp = 2 days

Application in Warranty Inspections

For warranty inspections that require a thorough review of every module on a PV system, aerial inspections by drone are completed in a fraction of the time when compared against human labor. The inspection and, which normally takes weeks, will take a drone a day or two (for commercial-scale and utility-scale systems. Once all imagery/data of the site has been collected with the drone, the data analysis and the creation of a detailed, clear, and actionable report with Raptor Maps can be completed in days. The process to identify modules with the warrantable issue is 1000 times faster. Instead of spending valuable time and labor on the inspection to find anomalies, you can spend this time on investigating the problems in more detail and laying out your warranty claim. 

Drones have a wide capability of what can be found. They’re able to detect:

Large scale issues.

Inverter Anomaly Identified on Solar PV Plant.

Module defects.

One of many diodes identified during a warranty inspection.

Cell level anomalies. 

Cell level anomalies are easily identified with thermal cameras.

If it can be identified visually, a drone will be able to find the problem. The Raptor Maps built report, will localize, and prioritize the defect so you know the severity of issues that are affecting your solar PV site. 

Image from a Raptor Maps report showing affected modules, and their location and severity.

Drones and Software Benefits

For anomalies that require thermography and can’t be seen by the eye, drones deliver the capability to detect thermal anomalies and accurate temperature deltas of those anomalies. This information enables you to know which modules are functioning correctly, and which are not functioning correctly. The data collected with a thermal drone also enables you to identify where the anomaly is located in the PV system down to the module level. When following the IEC standards for aerial thermography of a PV system, capturing the data at 3cm/px enables very specific detail to be reported on, and gives the warranty claims a stronger foundation as well. The thermal image resolution is critical for the accuracy of the findings. Using a manned aircraft/plane cannot deliver this high-level resolution and detail in thermal image resolution.

High-resolution image of a solar PV system flown at 1cm/px GSD showing module cracking.

Standardization

Inspections are also standardized when using a drone and data analysis software like Raptor Maps for your warranty inspections. We have strict data requirements for acceptable imagery. You’ll receive the same level of quality in each inspection analyzed through this process. Standardizing the inspection will allow you to build a database of more in-depth reference points, and create a higher level of certainty of correct anomalies because all inspections were performed and analyzed the same way, each time. 

When every aerial inspection of a PV system is performed the same standardized way and all data is reviewed by the same tool such as Raptor Maps, you are able to find recurring issues. This also enables you to take note of anomaly trends and further diagnose root causes including issues that could be due to a manufacturer defect or installation error.  Properly identifying the root cause with standardized data and reports enables you to file a warranty claim and replace the component instead of constantly addressing the same problems and increasing labor onsite. 

We have heard from several companies that own, manage, and maintain solar assets that the need for regular inspections up O&M costs. PV systems built with components that have known issues and require these regular inspections to catch new warrantable issues consumes significant time and labor bandwidth. Though the costs can be calculated and possibly budgeted for, using drones for these ongoing inspections and a credible software solution will reduce the amount of labor required. However, drones combat this and allow for time to be spent on other matters, and/or further investigating or field addressing the anomalies. 

Conclusion

In close, applying drones and software technology is an easier, less expensive, and more efficient way to inspect your solar PV system for warranties. The accuracy of the thermal cameras allows you to identify anomalies and track trends to build a robust case for the warranty claims. 

If you want a more in-depth breakdown of thermal drones application in solar inspections, check out our free 5-part webinar series created with FLIR!

If you would like to learn more about how using drones and software can support solar inspections for warranties please contact us HERE or email us directly through info@raptormaps.com. We can also help you learn more about our software that converts your inspection imagery into final reports that are accurate and easy to use for asset management and maintenance.