As renewable energy use continues to increase in scale each year, newly discovered technologies are crucial for advancing the industry. One such example is using infrared drones to inspect solar farms and commercial rooftop PV systems. Previous methods of inspections like handheld thermography and I-V curve tracing are beginning to become outdated processes that are much more expensive and time consuming in comparison.
It has been proven that drones are up to 70% faster and 40% cheaper than manual solar inspections. Industry averages of savings per MW after implementing drones amount to over $1,900!
Prepare yourself as we take flight and uncover just how much money infrared drone solar inspections are saving PV asset owners, solar companies, and O&M teams.
Table of Contents
Drone vs Manual Inspections
Traditional manual field inspections whether it be handheld thermography, electrical, or I-V curve tracing are time-consuming, incomplete, and very expensive.
There is an industry standard practice where only a small sample size of modules are manually inspected, usually 10-25%. Doing this cuts costs and saves crew hours but in return provides inaccurate and incomplete data. The solar O&M company Aerospec Technologies estimates that it takes a technician roughly 25 hours to inspect 1MW on foot. At the American national average wage of $29/hour, it would cost approximately $3,625 to fully inspect a fairly small 5MW farm.
| Farm Size (MW) | Manual Inspection Cost | Manual Inspection Time | Drone Inspection Time |
|---|---|---|---|
|
5 MW |
$3,625 |
125 Hrs |
1 Hr |
|
10 MW |
$7,250 |
250 Hrs |
2 Hrs |
|
20 MW |
$14,500 |
500 Hrs |
4Hrs |
|
30 MW |
$21,750 |
750 Hrs |
6 Hrs |
|
50 MW |
$36,250 |
1,250 Hrs |
10 Hrs |
|
75 MW |
$54,375 |
1,875 Hrs |
15 Hrs |
|
100 MW |
$72,500 |
2,500 Hrs |
20 Hrs |
Data estimations from average industry calculations.
The greatest advantage of aerial inspections is its speed. On average, drones are able to collect data 70% faster than manual methods while having 99% accuracy.
This increase speed even more and allows for a total inspection of a site to be completed in a much shorter time frame and ensures that every module has been accounted for.
Malfunctioning modules, strings, combiners, or inverters that may not have been detected using traditional inspection methods can be quickly identified and repaired, increasing overall site yield.
One solar asset owner estimates that they save $383,127 annually by repairing defective modules that likely would not have been discovered during on-foot inspections.
Revenue Loss Estimations
Furthermore, aerial thermography inspection data is capable of rapidly providing actionable information. Reports utilize the drone data to estimate potential revenue losses of found anomalies by taking into consideration local power rates and climate. Detailed information that is typically included in the reports consist of:
An interactive map of the solar plant with every anomaly geo-reference.
A reference-able table describing all possible anomaly types with photos.
Discovered fault types paired with corresponding visual and thermal photos.
Estimated annual impact in kWh and lost revenue if anomalies stay unresolved.
In House or Outsource?
A very commonly asked question is whether you should outsource your drone solar inspections to experienced and reputable drone companies or develop an in house program by training your own pilots. Both have there own benefits, and in the end it comes down to 3 questions:
HAVE QUESTIONS ABOUT droneS? START HERE.
1. How Many Inspections do you Need to Perform?
Taking into consideration the number of PV systems you operate along with the fact they usually need to be inspected only once a year, how often will you need to utilize the technology? For large national solar and O&M companies it can make sense as they have hundreds or even thousands of sites to maintain, but for the smaller businesses it may not be as black and white.
2. Do you have the Financial Capital?
It is clear that infrared drone solar inspections is a very niche industry. And it may be surprising to most that the initial equipment, training, and software investment will exceed $30,000. This is the entry level price to get started and there isn’t many corners to cut without hurting your bottom line.
Having the best in class equipment is a requirement if you want to achieve the most accurate and valuable data. Most commonly used is the DJI Matrice 300 drone with the Zenmuse H20T thermal sensor.
The Matrice paired with the H20T, makes for the ultimate platform for aerial commercial inspections. A key major benefit of the H20T infrared camera is its combination of visible RBG pictures with thermal. In simple terms, there are 2 cameras that take photos and video at the same time for easy referencing and comparison.
Cheaper solutions exist such as the DJI Mavic 2 Enterprise Dual and Autel Robotics EVO II Dual to name a few. However these camera resolutions are significantly lower and most drone post processing softwares won’t accept the images.
Another thing to think about is the shelf life of these aircraft and cameras. The drone industry is evolving rapidly each day and the average service time is only around 2 years before new equipment is released and an industry shift occurs. However, you won’t need to worry about reaching the ROI on your equipment when you outsource with a drone service provider.
What's included in YOUR GUIDE...
Techniques for Exposing Warrantiable Items on Your PV Sites.
A Proven Roadmap for Successfully Implementing Drones in Solar.
Strategies for Identifying DC Losses and Avoiding Downtime.
3. Can you Afford to Hire Several more Employees?
The largest PV companies and O&M teams like SOLV and Enel have dedicated teams who travel the country to perform UAS infrared inspections. However, most smaller companies don’t have the resources, time, or number of assets that justify these specific roles.
The level of training and expertise needed to perform these operations correctly isn’t something that can be learned on a Saturday afternoon either. It can often take several months to study and implement the material. Types of licenses, certifications, knowledge, and procedures that are required include:
- FAA Part 107 License
- Airspace knowledge
- Preflight checklists
- Aircraft care and maintenance
- Emergency procedures
- sUAS thermography certification
- Flight planning
- Flying in different flight modes
- Operating in coordination with manned aircraft
- Correct camera and flight settings
- Suitable weather conditions
- SOP’s
- Risk management
- Liability
- Staying current with changing laws
- Battery voltages and proper storage
- Analyzing drone data
- Aircraft registration
Looking at the advantages and disadvantages of having both internal or external programs, the assumption can be made that it depends on your specific company. Having an understanding of your needs and resources is crucial when making the decision.
And in the end, most solar companies and O&M teams prefer to hire true drone professionals who have the experience and education needed for solar inspections.
Industry Case Studies
So we all know that drones are saving money and have faster inspection times, but what kind of faults are being detected and how much money has been saved? To answer those questions, here are 3 case studies which in total saved PV owners nearly $500,000 annually.
79 MW Site, Arizona U.S.
This 79 MW PV system was inspected before the annual preemptive maintenance visits. The drone data revealed that the site was heavily impacted by over 13 types of PV system anomalies, with over 10,000 offline modules.
The largest and most impactful issues included 50 inverter faults, 8 offline strings which were estimated to reduce production capacity by 84 kW, 64 module level issues, and 594 sub-module level anomalies.
In total:
- 13 anomalies were identified affecting 10,967 modules
- 3,434 kW or 4.37% of modules had faults
- Annual financial loss if the anomalies stayed unresolved would amount to $184,731
5.9 MW Site, Minnesota U.S.
This 5.9 MW PV system was inspected as part of an annual preventative maintenance protocol. A drone was flown for three hours and provided the operations and maintenance team with sub-modular anomaly details through thermal and visual spectrum imagery.
The inspection showed anomalies from the inverter level down to the cell level. The results uncovered 490 system anomalies, categorized into 16 anomaly types, and amounting to 2,853 affected modules.
In total:
- 422 anomalies were identified affecting 2,853 modules
- 378 kW or 6.56% of modules had faults
- Annual financial loss if the anomalies stayed unresolved would amount to $17,447
199 MW Site, California U.S.
This large utility-scale PV system’s O&M vendor was notified by internal monitoring systems that the site was significantly underperforming. Due to the large size of the site, more than 1000 acres, and difficulty in locating the causes of underperformance with PV system monitoring tools such as field walks and IV-Curve tracing would have cost the team significant time and labor resources.
Drone pilots were able to finish the inspection in a total of 10 days. The findings uncovered performance issues that fell into 6 categories, totaling 3,114 anomalies. There were almost 20,000 impacted modules which amounted to over 7 MW of production lost.
In total:
- 6 anomalies were identified affecting 19,013 modules
- 7,404 kW or 3.7% of modules had faults
- Annual financial loss if the anomalies stayed unresolved would amount to $296,196
$635 Million Saved
Drone use in the solar industry has seen a 36% increase in the last year.
For the past 2 years, drone software company Raptor Maps has been tracking drone data collected from PV systems between January 1, 2019 through December 31, 2020 through various asset managers, operations and maintenance (O&M) teams, engineering firms, and drone service providers.
It was calculated that the use of drones in solar has saved $200 million in maintenance costs in 2019 and $435 million in 2020 respectively.
Calculating ROI
The speed and accuracy of aerial inspections slash technician labor costs while providing a more comprehensive view of system performance. Combining money saved on technician’s wages with performance gains from site production, O&M managers will likely find that aerial inspections lead to increased revenue.
But what can you do to evaluate if infrared drone solar inspections are right for your business? Here are the key factors to consider:
- How often are your sites inspected?
- Which inspection method(s) do you currently use?
- How thorough are your inspections?
- How do you keep track of located faults?
- How comprehensive is your data?
- Do your inspections require plant downtime?
- What are your current inspection costs?
- How long do your inspections take?
What's included in YOUR GUIDE...
Techniques for Exposing Warrantiable Items on Your PV Sites.
A Proven Roadmap for Successfully Implementing Drones in Solar.
Strategies for Identifying DC Losses and Avoiding Downtime.
