Is a China-U.S. trade war brewing over green technology? Reuters takes an in-depth look this morning at a looming battle between the two countries over fair vs. unfair support of wind and solar industries, as laid out in a massive complaint filed by the United Steelworkers union. The complaint accuses China’s government of breaking World Trade Organization rules by subsidizing solar manufacturers like Suntech, LDK Solar, Yingli and Trina Solar, helping them flood the market with cheap panels and turbines and undercut U.S. and European competitors. The Obama Administration has already made similar complaints to the WTO over Chinese government backing of its wind power manufacturing sector. While Chinese panels and turbines sprout up across the U.S. and Europe, China’s domestic market remains hard for foreign competitors to crack into, though that’s also a measure of how small that domestic market is, even if it’s growing fast. U.S. thin-film solar panel giant First Solar has landed a big project in China, but it’s faced plenty of opposition from would-be Chinese rivals. Stay tuned for more news from Chinese President Hu Jintao’s visit to Washington D. C. this week.