China's at the head of the pack in pollution, emitting more total carbon dioxide than any other country, but it's also leading in efforts to move from fossil fuels to renewable energy sources by producing the most wind turbines and solar panels.

Koelnmesse, a German event planning company, and the China Electricity Council invited the thinkers and the investors behind green energy to the opening of the 2011 Clean Energy Expo on Wednesday. Eager to take part in China's clean energy market, 320 companies from 22 different countries displayed their businesses on the exhibition floor.