Solar farms with wildflowers triple insect numbers in Minnesota

The Story in Brief

Wildflower-covered solar farms in Minnesota have tripled insect abundance and boosted native bee populations twentyfold, according to a five-year study by Argonne National Laboratory. Two retired agricultural sites near Ramsey were seeded with native prairie grasses and wildflowers instead of gravel or turf. Researchers counted insects annually and found that as plantings matured, bees, butterflies, wasps and hornets increased significantly.

The habitat also attracted 73 bird species, including some nesting in panel supports. Raising the solar arrays higher allowed more native growth with minimal extra cost, and native prairie maintenance proved cheaper than gravel over 25 years, about $14,150 per acre versus $25,000. However, only 24,000 of the roughly 600,000 acres of US utility-scale solar currently have documented pollinator habitat, and voluntary state scorecards lack monitoring. A new certification requiring 15% native vegetation is being drafted.