The answer is to know the WHO, WHAT, WHEN, and WHERE of your project. WHO are you collecting data for/ WHO is collecting your data? WHAT are you looking for (types and/or level of detail of anomalies on site)? WHEN are you collecting your data? WHERE is the inspection occurring (geographic location of the site)? The WHY of aerial drone solar inspections is simple: using drone inspections in the solar industry optimizes your workflow, increases productivity, reduces labor costs, and improves safety.
One of the most important, yet overlooked is the WHEN aspect of data collection. Factors including season, weather, and the time of day the drone inspection occurs can dramatically impact thermal data. Whether a solar asset owner, O&M company, or service provider, the quality of drone solar inspection data matters.
Keep reading as we break down the following WHEN factors:
- Time of Year
- Time of Day
Inspections of solar assets are best performed in clear, sunny weather months. Although it depends on the geographical location of the solar site, drone inspections during the spring, summer, and early fall tend to produce the best data because of their tendency for high irradiance. In fact, irradiance on a clear summer day can be up to 20 times higher than on a cloudy winter day. The sun, warmer climate, and higher irradiance associated with these seasons allow for site anomalies such as hot spots and string/module failures to be more visible in thermal imagery. The long days during summer months also allow for a larger window to collect high-quality data. Extended hours of sunlight will provide you with greater opportunity to collect proper data and also allows you time to re-fly if needed.
2. Fly in Perfect Weather Conditions
Flying when the sun is shining is the most important weather factor to take into account. High irradiance produces clear data and makes defects evident when performing post-processing/data analysis. According to the National Renewable Energy Laboratory, the recommended minimum irradiance to perform thermal inspections is 600 W/m2. This describes the amount of solar (radiant) power per surface unit area necessary to perform thermal inspections. Pay extra attention when flying at high latitudes in the winter during low-irradiance conditions since. Low wind conditions are also a must in order to keep your drone on the mission course, preserve its battery life, and capture images free of motion blur and glare.
3. Midday Flights Lead to Quality Data
High irradiance, as stated before, is a key factor for collecting quality data. With the sun at its highest, and irradiance at its strongest, midday flights tend to produce the highest quality data. However, stay away from performing inspections close to, or around noon in order to avoid glare in your data set. Plan to start data collection mid-morning so you can collect, review, and re-fly (if needed) during high irradiance hours.
In conclusion, WHEN you fly your solar assets can make or break your thermal data. Look to collect data in the summer months where the sun is strong, the wind is low, and there is an ample amount of time to perform your drone solar inspection. Learn more about collecting thermal data by watching our webinar with FLIR Systems here.