SHANGHAI -- In 2007, Ren Junjie, an energy service company executive, came up with an idea for a business. He intended to persuade Chinese factories to use his money and technology to improve energy efficiency. Then the factories would pay him back with part of the saved energy costs. At first, his plan went nowhere. His clients had a hard time understanding such a service, and giving them brochures didn't help. So Ren dragged along a set of books and taught his new clients what amounted to Economics 101. Now, when Ren goes to business meetings, he no longer needs to bring his books with him, and his company, Volt Tech, has made a large number of deals with factories to retrofit systems and share the benefits from lower utility bills.

SHANGHAI -- China on Friday opened anti-dumping investigations into imported polysilicon from the United States and South Korea, the latest signal of a growing tension in the global clean-tech trade. Polysilicon is a key material used in solar panel production. More than two-thirds of China's polysilicon imports in the first quarter of this year came from U.S. and Korean producers. But Chinese polysilicon producers have accused their foreign peers of selling the goods below production cost, China's Ministry of Commerce said in a statement issued Friday.