Khosla Ventures InvestmentsVC Ratings blog provides a list of 26 renewable energy startups that Vinod Khosla's - Khosla Ventures' has invested in. He is well known for his investments in biofuel related companies, but the list reveals a much broader scope.    
* Cellulosic - Mascoma, Celunol, Range Fuels, 1 stealth startup
    * Future Fuels - LS9, Gevo, Amyris Biotechnologies, Coskata Energy
    * Efficiency - Transonic Combustion, GroupIV Semiconductor, 1 stealth startup
    * Homes - Living Homes, Global Homes
    * Natural Gas - Great Point Energy
    * Solar - Stion, Ausra
    * Tools - Nanostellar, Codon Devices, Praj
    * Water - 2 stealth startup
    * Plastic - Segetis, 1 stealth startup
    * Corn/Sugar Fuels - Altra, Cilion, Hawaii Bio
http://thefraserdomain.typepad.com/energy/2007/04/vc_ratings_blog.html