Workers check the Dongci rooftop photovoltaic power station in Hengdian town of Dongyang city, East China's Zhejiang province, April 9, 2017. The Hengdian Dongci rooftop photovoltaic power station, with total investment of 200 million yuan (about $29 million), has generated 75 million kWh of electricity since April 2013. [Photo/Xinhua]