Paul Kedrosky has a list, via TheDeal.
1) Cellulosic – Mascoma, Celunol, Range Fuels, 1 stealth startup
2) Future Fuels – LS9, Gevo, Amyris Biotechnologies, Coskata Energy
3) Efficiency – Transonic Combustion, GroupIV Semiconductor, 1 stealth startup
4) Homes – Living Homes, Global Homes
5) Natural Gas – Great Point Energy
6) Solar – Stion, Ausra
7) Tools – Nanostellar, Codon Devices, Praj
8) Water – 2 stealth startup
9) Plastic – Segetis, 1 stealth startup
10) Corn/Sugar Fuels – Altra, Cilion, Hawaii Bio
