Sometimes there are obstructions shading the location where solar panels are going to be installed. It is critical to evaluate shading over the course of the days of the year and hours of the day.
Back in the “old days,” we used some industry-specific manual tools and paper charts. We could accurately evaluate the shade location on a given day and hour. While it was accurate, it was expensive and time-consuming. The tools were expensive themselves and the evaluation required significant time on site. It also lacked the visualization capabilities we have today.
Nowadays we use 3D computer models that are geolocated. High-resolution aerial imagery obtained from professional satellite imagery companies forms the basis for the models. We can place trees, buildings, poles, overhead wires, and other potential shading obstacles.
For this client, we were challenged with a 2-story house adjacent to the client’s 1-story house. We determined that it would be ideal to restrict shading on the solar panels outside the hours of 9:00 am to 3:00 pm. To do that we needed to look at the worst-case scenario – the winter solstice (usually on December 21).
The software we use calculates the sun’s position relative to the model and casts shadows realistically. We can take imagery and even video from these renderings to show clients. We analyze the situation and determine the offsets needed to maximize solar production and locate solar panels ideally given any other limitations that exist.
Quick, Easy, and Accurate
It’s all pretty amazing and done from the comfort of our office. Sometimes a quick site analysis is needed to assess the height of obstructions, but we can usually use street views or oblique imagery to get a pretty good idea. Trees also grow, so we err on the side of caution when sizing natural obstructions.
The results of this analysis showed us that we needed to keep solar panels at least 4 feet away from the eave of the home on the west roof. When it comes time for engineering, permitting, and installation, we will proceed with confidence. Shading will not severely impact the output of this solar energy system.