The Pros and Cons of Different Types of Solar Site Inspections

22 March 2018

Solar asset managers want their sites to be productive and efficient. With the growing demand of solar energy it's never been more important to regularly inspect solar sites to ensure maximum profitability. There are three primary methods used today and in this post we’re going to show you the key differences between each of these methods.

Handheld Ground Inspection

Handheld inspections involve an operator who physically monitors every module on a solar site. This is a typically safe and non-invasive inspection method that focuses primarily on visible issues. When operators are equipped with thermal imaging cameras they are able to address issues up to cell level, however; operators need to have a very good knowledge of thermography to be able to make judgments on the spot. Even with this advantage, it's still very difficult to detect string anomalies due to the proximity. Scalability is also another issue. It can be time consuming to have an operator perform these physical inspections, which often don’t have a really comprehensive cell anomaly overview. In most O&M contracts today thermography is included for up to 10% of the panels, performing inspections based on statistical sampling. Additional inspections can have an additional cost of 2 to 3 cents per kWh in Northern Europe; therefore the exponential effort required to scan larger sites makes this method quite expensive in an environment where most O&M providers need to keep costs down. Consolidation of resulting data in a single platform is also a big disadvantage of this particular method.

Pros Cons
  • Structural review of site 
  • Not scalable
  • Very time consuming data acquisition
  • Difficult to detect multiple string anomalies
  • Expensive
  • Consolidation of data in a single platform

Manned Aerial Inspection

Manned Aerial Inspections use aircrafts equipped with thermal imaging cameras to detect module and string anomalies on a solar site. One of the main disadvantages, however; is the aircraft requires a higher flight altitude, which can result in a lower resolution / quality image. This is an extremely important criteria to be able to detect certain types of anomalies, for example, hotspots, PID's and Junction Box anomalies. Not having a complete picture of all site anomalies means it's very difficult to pinpoint the root causes of issues with more certainty. To compensate for the data gap, it's common to combine this method with handheld thermography. This method is more cost effective than the handheld one alone, but because it’s a manned aircraft, it can still be an expensive uncomplete option. Because of the equipment and aircraft requirements, it can take longer to deliver of the complete end-to-end solution.

Pros Cons
  • Fast
  • Detects more anomalies than handheld
  • Multi-layer imaging
  • Low image quality / resolution
  • Doesn't provide a complete picture
  • Slower delivery time of end-to-end solution
  • Can be expensive

Unmanned Aerial Inspection

Unmanned aerial inspections, primarily with drones, have become an essential tool for solar sites because they provide repeatable reliable measurments up to individual cell level at significantly reduced inspection time and cost. This type of inspection truly combines the best of the previously described methods: it can detect both the small cell-level problems and larger string anomalies. Drone inspections are scalable and easily deployed accross multiple sites. When combined with an analytics tool powered with machine learning algorithms that can detect and classify anomalies, drone inspections can be a game-changing solution for solar enterprises. One of the main challenges with this method is that as the industry grows, it can be difficult for solar asset managers to find the right providers to cater to their specific inspection and mapping needs.

Pros Cons
  • Provides cell, module and string level accuracy
  • Multi-layer imaging and various data models
  • Accurate analytics to consolidate and analyze data
  • Scalable
  • Slower data acquisition compared to manned

At DroneGrid, we believe in the power of aerial intelligence to deliver these benefits to your sites.

Contact us today to learn how we can help your solar site achieve operational efficiency.