Effects of photovoltaic panels on soil temperature and moisture in desert areas

Photovoltaic power generation is an important clean energy alternative to fossil fuels. To reduce CO₂ emissions, the Chinese government has ordered the construction of a large number of photovoltaic (PV) panels to generate power in the past two decades; many are located in desert areas because of the sufficient light conditions. Large-scale PV construction in desert areas can alter the local microclimate and soil conditions, thereby affecting the growth of vegetation. However, few studies have focused on the effects of PV panels on the environment of desert areas. In this study, we investigated the effects of PV panels on soil moisture and temperature via a whole-year field experiment at a PV power plant in a desert area in western China. The in situ soil moisture and temperature at a depth of 0-0.4 m were measured under three types of PV shading conditions: shaded by fixed-tilt (FIX) PV panels, shaded by oblique single-axis (OSA) PV panels, and no shading. The results showed that the soil temperature and moisture at sites under PV shading were significantly affected compared with those at sites without shading. PV panels increased the average soil temperature during winter but decreased it during the other three seasons. Moreover, the warming effect of FIX PV panels on the soil is more apparent than that of OSA PV panels. PV panels have positive effects on soil moisture. Compared with that at the sites without shaded areas, the average soil moisture under the FIX PV panels and under the OSA PV panels increased by 14.7% and by 11.1%, respectively. These data provide support for future studies on vegetation restoration around PV power plants in desert areas.