PS 38-50 - The ecological impacts of solar energy development in the southwestern U.S. with a case study from the Gemini Solar Project

Abstract: To meet renewable energy targets, solar energy development is expanding rapidly throughout the United States. In 2023, the U.S. plans to add nearly 30 gigawatts of utility-scale solar energy capacity – the most of any year to date. Although solar energy can reduce carbon emissions relative to more traditional forms of energy, it has an intensive land use, requiring approximately 1.8 times as much land as surface-mined coal, and 15.8 times as much land as natural gas, for the same energy generating capacity. Much of the solar energy capacity is being developed in the southwestern U.S., where there is large solar irradiance across the Mojave, Sonoran, Chihuahuan, and Colorado Plateau Deserts. However, these deserts are sensitive to land use disturbance, and the environmental consequences associated with solar energy land conversion are predominantly unknown or only beginning to be understood.

To fill this knowledge gap, we present a novel framework for predicting the impacts of solar energy development to plants and wildlife by linking disturbance types associated with solar facility construction and operation to the morphological, physiological, life history, and behavioral traits of species and guilds. In the absence of empirical research on the impacts of solar development on the many organisms affected, this framework provides insights and suggests pathways for future research. Guided by this framework, we present the Gemini Solar Project as a case study. The Gemini Solar Project is a utility-scale photovoltaic solar energy development, located in the Mojave Desert northeast of Las Vegas, Nevada. Disturbance types during the construction phase of the project include driving over and crushing vegetation, soil destabilization, road traffic, and noise pollution. We quantify declines in native perennial plant cover, plant species richness, biocrust cover, and soil stability resulting from construction activities, and compare these measured results to those predicted by the framework. We also demonstrate shifts in the plant community composition under and between photovoltaic panels. Our work highlights new insights to fill the current gap in our understanding of the impacts of rapidly expanding solar energy development and contributes a predictive framework for evaluating impacts to species and guilds.