In our latest Clean Energy Trends 2010 report, we found reasons for the clean-energy sector to be hopeful. At the same time, we found a number of not-so-insignificant question marks surrounding the future of clean energy. These include the rise of China as a clean-tech leader and what it means for other nations; the current lack of reliable and sustainable financing for technology and project development and the need for new innovative financing models like "green banks;" and the issue of when and if initial public offering (IPO) markets will return so that early-stage investors have a viable "exit" strategy for their portfolio companies.