Most of Vinod Khosla's environmental startups are efforts to reduce our dependence on petroleum -- both by making better use of oil and by finding other sources of liquid fuel. The rest address solar and geothermal power and desalination of seawater. Very broadly, his green-tech portfolio falls into three clusters:
Fuel Efficiency: To lower the cost of driving, EcoMotors and Nanostellar are rethinking the diesel engine, Transonic Combustion is improving fuel injectors, and Tula is at work on new versions of microprocessors that monitor the operations of today's cars.
Alternative Fuels: Creating and refining ethanol are Cilion, Coskata, Ethos, Hawaii BioEnergy, LanzaTech, Mascoma, Praj, and Range Fuels. Amyris Biotechnologies, Gevo, KiOR, and LS9 are trying to commercialize other substitutes for petroleum.
Electric Power: Firefly Energy, Sakti3, and Seeo focus on batteries; Group IV, Kaai, Lumenz, Soraa, and Topanga, on lighting. Ausra, Infinia, and Stion do solar power, Altarock is in geothermal, and Great Point Energy aims to make clean-burning gas from coal.