Business Green: As US and Chinese diplomats face off in Copenhagen, one company is serving to highlight the huge environmental and economic benefits that could accrue from improved collaboration between the two economic giants. Engineering giant General Electric (GE) reported earlier this week that its Ecomagination clean tech products and services generated sales in China of $656m (£404m) during the first half of the year, an improvement of 50 per cent on the same period in 2008. The company …