Effects of Revegetation on Soil Physical and Chemical Properties in Solar Photovoltaic Infrastructure

Abstract

Solar photovoltaic (PV) technology is being deployed at an unprecedented rate. However, utility-scale solar energy development is land intensive and its largescale installation can have negative impacts on the environment. In particular, solar energy infrastructure can require extensive landscape modification that transforms soil ecological functions, thereby impacting hydrologic, vegetative, and carbon dynamics. However, reintroducing native vegetation to solar PV sites may be a means of restoring their soils. To this end, we investigated critical soil physical and chemical parameters at a revegetated photovoltaic array and an adjacent reference grassland in Colorado, United States. Seven years after revegetation, we found that carbon and nitrogen remained lower in the PV soil than in the reference soil and contained a greater fraction of coarse particles. We also found that the PV modules introduced heterogeneity in the soil moisture distribution, with precipitation accumulating along the lower edges of panels. The redistribution of soil moisture by panel arrays could potentially be used in concert with planting strategies to maximize plant growth or minimize soil erosion, and should be considered when evaluating the potential to co-locate vegetation with solar infrastructure.

Microhabitats associated with solar energy development alter demography of two desert annuals

“…Matrix models (Caswell 2001) were built for the target species using rates obtained in the Control, Runoff, and Shade microhabitats over the seven-year period 2012-2018. Separate experiments for each life stage were used to estimate belowground and aboveground demographic rates needed to parameterize models, avoiding seed bank disturbance otherwise needed to obtain seed survival and germination estimates.…”

“…Photovoltaic (PV) panels create novel shade and moisture gradients that overlay natural microhabitats created by topographic variation (Smith et al 1987. Solar energy facility designs that retain ecological functions have been recommended as a means to increase the sustainability of solar energy development (Moore-O'Leary et al 2017, Hernandez et al 2019, and plant communities have been retained or restored under panels in some locations (Beatty et al 2017, Walston et al 2018, Choi et al 2020). To develop best management practices that mitigate adverse solar energy development impacts, as mandated by state and federal policies, we need to understand how plant vital rates and population trajectories are affected by PV solar energy infrastructure.…”

“…Population growth models integrate species performance across the life cycle and predict population-level consequences (Caswell 2001, Salguero-G omez et al 2012, providing an effective tool to compare species responses to the novel microhabitats generated by energy infrastructure. For annual plants, population growth models can also be used to explore effects of microhabitat variation on belowground vs. aboveground life stages, yielding a more comprehensive assessment of the mechanisms underlying species resilience or vulnerability.…”

“…We applied belowground seed survival rates obtained in a concurrent experiment (Hernandez et al 2020), measured rates at which seeds germinated and emerged as seedlings, and tracked seedlings through reproductive maturity over a seven-year period. We used these data to parameterize matrix models (Caswell 2001) to analyze population growth and sensitivity to varying life cycle transitions under contrasting microhabitat conditions. Model projections represent the cumulative demographic impact of each microhabitat across life stages, manifesting as relative population growth.…”

The Land Sparing, Water Surface Use Efficiency, and Water Surface Transformation of Floating Photovoltaic Solar Energy Installations

“…While there has been rapid development of FPVs, there has been a lack of research on the technical, hydrological, and spatial attributes of FPVs, specifically compared to ground-mounted PV [1,6,7]. The local recipient environment of ground-mounted PV installations impacts panel performance and lifespan [8], while the construction and operation of ground-mounted PV installations can impact the environment in which it is sited and its associated ecosystem services [2,[9][10][11][12][13][14][15]. Similarly, the siting of FPVs may impact panel performance as evaporation between the water body surface and the panel lowers ambient panel temperature and disperses additional heat from the panel area [16,17].…”