The second phase of the world's highest-altitude photovoltaic project began operations in Shannan Prefecture of southwest China's Xizang Autonomous Region on Saturday. The new phase of Huadian Xizang Caipeng Photovoltaic Power Station uses cutting-edge "bifacial" photovoltaic panels, whose rear side can absorb light reflected from the ground or snow, enhancing efficiency by 20 percent compared with single-sided panels.