Farmers have planted shrubs and trees around their fields for centuries to redirect wind flow and protect their crops and soils, so it stands to reason that an “outcrop” of solar panels might divert winds in some way.
“We had a pretty good idea there was going to be an interaction between the wind and solar panels,” Etyemezian says. “So the question then was to be able to measure this and have some numbers on it.”
To get this quantification, the scientists measured the wind speeds and directions outside of a utility scale solar facility near Las Vegas and also made the same measurements inside the solar installation, in between successive rows of panels. They recorded these variables at ground level at several different distances between successive panels.
The scientists found that if the winds were from the south, the panels, which were south facing, reduced the wind speed between the panels. When the winds came from the north, the panels again reduced the wind speed but the scientists observed localized areas where near-ground wind shear increased. Such wind shear can lead to scouring of loose sediments, Etyemezian says, “So the average goes down but the localized effects go up.” When the winds had strong easterly or westerly components, the panels, which are orientated in east-west rows, straightened the winds into pure easterly or westerly directions.
The findings expose the influence of panel orientation on prevailing winds and Etyemezian hopes that this knowledge will help in the design of efficient solar installations. “If you’re not protecting that surface with the orientation of the array but you are, in fact, allowing the wind to channel through the panels, then you might have a dust problem where you didn’t have one before,” Etyemezian says. “We’re hoping that having this kind of model at least provides designers with some basic guidance on what to look for.”