A worker works at the Three Gorges' underground power station in Yichang, central China's Hubei Province, Jan. 2, 2011. The underground turbines were being installed at the underground power station. Two underground turbines of the hydropower project are expected to be put into operation before June 30, 2011. A total of six 700,000 kw underground turbines are planned to be installed at the underground power station. [Xinhua]