In what appears to be a sign that we may be in a bubble, November and December are offering up 3 large cleantech conferences from some of the most connected groups around.

November 10-11, 2008: JUCCCE China Energy Forum: Partnering on Solutions
November 18-19, 2008: US-China Green Energy Conference ‘08
December 3-5, 2008: Cleantech Forum Shanghai from the Cleantech Group

The topics are all very topical, very important, and their speakers are all executive level representatives from government, industry, and finance (NGOs are in short supply as usual at CSR/ sustainability conferences).

Were I living abroad and having to pick one to go to I would have a tough time selecting, but fortunately there is a lot of overlap between the three (topics and speakers)

I would say it is best to identify the one that offers the most content for your particular interest/ background, and hope that next year the orgnizers will find a way to come together in a single super conference that brings people together…rather than divide and quarter them