Workers examine windmill hubs in Shandong Rongchuan Port Machinery Manufacturing Co. Ltd. in Rongcheng, Shandong Province, on May 16, 2011. Being a coastal city, Rongcheng attracts large energy companies to invest in wind power projects with operational and under-construction installed capacity totaling 250,000 kw and accumulative electricity generation of 600 million kwh (GUO XULEI)