Large-scale Solar Development: Water Quality Risk, or Green Infrastructure? The PV-SMaRT Project [virtual]

Wind and solar energy are now the least expensive form of electric energy generation in world, including in the U.S. Consequently, the market for renewable energy projects is surging, with large-scale projects being proposed in every state in the nation. Large-scale PV solar projects, in particular, present unique and uncertain risks and opportunities to water quality and watershed functions. The U.S. Department of Energy has funded the Photovoltaic Stormwater Management Research and Testing (PV-SMaRT) project to evaluate water quality impacts of large-scale solar development. The study will create solar-specific runoff co-efficients that consider type of ground cover, soil type, hydrology, slope, and solar array design based on field testing across the nation and 3-D modeling.
The analysis is modeling the post-construction infiltration and runoff outcomes of large-scale PV for different design storm events under a variety of hydrologic conditions and site configurations. The field research focuses exclusively on the impact of ground cover choices and use of disconnection to mitigate for the volume and velocity at the drip edge of the panel. Ground cover choices have mitigating effects, but which could vary substantially under different site conditions, site designs, and design storm events.
The study also documents water quality and stormwater permitting practices for solar development and how field research and modeling can affect these practices. One potential implication of the study is understanding the conditions under which conversion of agricultural or disturbed land to solar development with appropriate ground cover could meet green infrastructure goals of improving water quality outcomes within impaired watersheds.