Solar projects can be an excellent opportunity to benefit insect pollinators like butterflies and bees.
Solar power or photovoltaic projects are becoming more and more frequent in western landscapes. Meanwhile, pollinator habitat and nectar resources are declining, negatively affecting ecosystems and agricultural productivity. Non-rooftop solar projects can have a large environmental footprint. For example, a solar power project in southern Idaho occupies nearly 1,000 acres. Land management practices at photovoltaic sites vary widely. At many solar sites the ground beneath is kept fallow (bare soil), leading to wind and water erosion and dust issues. Other sites allow native vegetation which is managed with routine mowing. The majority, however, are planted to low maintenance perennial grasses but offer few pollinator benefits. Co-locating solar fields with an understory of pollinator friendly plants can provide opportunities to manage the vegetation as valuable pollinator habitat.
Solar projects can be an excellent opportunity to benefit insect pollinators like butterflies and bees. The shade from solar panels has been shown to delay and extend the blooming period of many flowering species allowing for extended pollinator services. Additionally, a transpiring plant canopy below the panels creates a cooler environment than bare soil making the photovoltaic cells run more efficiently.
Solar projects, however, have certain restrictions and features, that set them apart from more traditional pollinator habitat plantings. The Aberdeen, Idaho Plant Materials Center recently released a technical note that summarizes the benefits of pollinator habitat in solar projects, and outlines practices for establishment and maintenance of pollinator habitat. Co-authored by Bradley Stokes, an entomologist with University of Idaho, the document provides guidance on site preparation, species selection, seeding, and management. It also provides tables of beneficial plant species, suitable for use in photovoltaic arrays under a variety of climatic and soil conditions. While the document contains information largely intended for Idaho landowners, it has broader application throughout much of the Intermountain West.
Idaho Plant Materials Technical Note No. 79: Establishing Pollinator Habitat in Idaho Solar Projects, can be found on the Plant Materials Program Technical Document website.
For additional information on specific species of plants, please see the USDA PLANTS database. Technical information and guidance on the use of conservation plants for pollinator habitat can be found on the Plant Materials Program website by searching for “pollinator” in technical documents or contact the nearest Plant Materials Center or plant materials specialist.