Ecohydrological effects of photovoltaic plants in Kubuqi Desert based on ecohydrological modeling and field observation

Photovoltaic (PV) power generation has attracted significant attention not only for its substantial carbon reduction potential but also as an emerging research focus regarding its ecological impacts, particularly in arid and semi-arid regions. The extensive construction of utility-scale PV plants on the desert areas alters near-surface microclimates, exerting non-negligible influences on ecosystems. While utility-scale PV plants significantly alter near-surface microclimates, traditional models often fail to capture the intricate feedback mechanisms between PV panels and the underlying surface. To address this gap, this study developed a novel ecohydrological model that explicitly integrates a physically-based PV canopy module into an existing ecohydrological model. Unlike conventional approaches, this model treats PV panels as a distinct canopy layer, allowing for the simultaneous resolution of energy and hydrological fluxes across the panel, vegetation, and soil interfaces. Validated at the Kubuqi PV power plant, located in the arid region of Northern China, the model demonstrated satisfactory performance. Results reveal significant ecological benefits at the Kubuqi PV power plant: gross primary productivity (GPP) increased by 110 gC·m^-2 during the growing season compared to the natural scenario, accompanied by a carbon sink enhancement of 58 gC·m^-2. This improvement is primarily attributed to a marked increase in water use efficiency (rising from 0.55 gC·m^-2·mm^-1 in the natural scenario to 1.12 gC·m^-2·mm^-1 in the PV scenario). Crucially, while the inter-panel areas functioned as a net annual carbon sink, areas directly under the panels acted as a carbon source. Although vegetation growth under the panels was suppressed by hydrothermal constraints, it exhibited higher water use efficiency, indicating enhanced resource utilization under limiting conditions. This research advances the understanding of PV effects on ecohydrological processes in arid and semi-arid areas and establishes a novel modeling framework integrating PV canopy influences for arid ecosystems.