The United States has slapped a second round of duties on wind turbine towers from China, ratcheting up tensions between the two countries in the renewable energy sector.

The U.S. Commerce Department said it was imposing preliminary anti-dumping duties of about 20 to 73 percent on Chinese-made steel towers. The decision is another victory for the Wind Tower Trade Coalition, a group of U.S. producers who say they are being driven out of business by unfair Asian competition.