Spatial disparity of utility-scale solar energy and the role of solar policy in the U.S.

Utility-scale solar energy (USSE) and rooftop solar PV generate about 70% and 30% of all solar electricity. While the adoption of rooftop solar in the United States (U.S.) has been explored in depth, how USSE is spatially distributed has yet to be discussed. This study examines the spatial distribution of solar power plants of 1 MW and above across regions of different socio-demographic characteristics in the U.S. and the impact of solar policy on the spatial distribution using the Geographical Detector Model (GDM) and Kernel Density analysis. The results show that: 1) the distribution of USSE has significant spatial disparity across different socio-economic communities and is not entirely following solar irradiance abundancy; 2) contrary to rooftop solar, USSE is more distributed in more ethnically diverse regions and regions with higher renter percent, which can mitigate the energy inequity issue in rooftop solar PV's tilt toward white communities and house owners; 3) similar to rooftop solar, USSE is also more adopted by groups of higher income levels; 4) The solar policy is an effective tool in promoting USSE but is also exacerbating the spatial disparity of USSE. The findings of this study help to understand better how to mitigate potential inequity during the energy transition toward a renewable and sustainable future.