I have worked in the solar industry, and "soiling" is highly dependent on soil, weather, proximity to roads, etc. And I've seen cases where it made a 30% impac

I have worked in the solar industry, and "soiling" is highly dependent on soil, weather, proximity to roads, etc. And I've seen cases where it made a 30% impact. In other locations, it is a non-issue, but vegetation was a hassle.