Biofuels: The Next Generation

As corn-based ethanol hits roadblocks, all eyes are turning to advanced biofuels. These, too, face difficult challenges, but that's not stopping a host of startups

THE FEEDSTOCKS (mainly cellulose-rich material, but also algae)

MUNICIPAL OR AGRICULTURAL WASTE
Pros: Cheap for now
Cons: Supply too limited to make billions of gallons
The Players: BlueFire Ethanol (trash); POET (corncobs); Verenium (sugarcane residue)

WOOD
Pros: Adequate supply in Southeast and other parts of the U.S.; easy to harvest
Cons: It's harder to extract cellulose from wood than from other feedstocks
The Players: Range Fuels, Coskata

ALGAE
Pros: Potential for high yields per acre
Cons: Scale-up is challenging; typically requires source of CO2 to bubble through algae
The Players: Algenol, Sapphire Energy, HR BioPetroleum, Solix, PetroAlgae

SWITCHGRASS, MISCANTHUS, AND OTHER SPECIALIZED ENERGY CROPS
Pros: Potentially vast supply; can improve soils; small carbon footprint
Cons: Challenges in establishing, harvesting, and delivering to biorefinery
The Players: DuPont Danisco (switchgrass); Verenium ("energy" cane); Iogen (wheat straw)

THE FUELS

ETHANOL
Pros: Can sell it into existing market
Cons: Limits on how much can be added into gasoline now
The Players: POET, Range, Mascoma, Verenium, Algenol, DuPont Danisco, Coskata, Qteros, others

BUTANOL AND OTHER MORE GASOLINE-LIKE PRODUCTS
Pros: Can be added to gasoline in large amounts and used in existing pipelines
Cons: Greater technological challenges; higher costs than ethanol
The Players: DuPont, BP, Gevo, Virent, Amyris

BIODIESEL AND JET FUEL
Pros: Works with existing infrastructure
Cons: May be difficult to produce economically
The Players: PetroAlgae, Solazyme (from algae); Amyris, LS9, Gevo, OPX (from any sugar)

THE PROCESSES (converting feedstock to fuel)

HEAT, CHEMICALS, OR MINERAL CATALYSTS
Pros: Potential to use wide range of feedstocks; catalysts can produce variety of fuels
Cons: May take more energy than biological processes and may require additional purification steps
The Players: Range Fuels, Coskata (heat feedstock to make gas); BlueFire Ethanol (strong acid, microbial fermentation); Virent (catalysts)

BIOLOGICAL (ENZYMES AND/OR MICROBES)
Pros: Depending on feedstock, the process is very energy-efficient
Cons: Has to be adjusted for each type of feedstock; enzymes are still costly
The Players: Solazyme (algae); Mascoma, Qteros (one-step microbes); Iogen, DuPont Danisco, Verenium (enzymes, microbes)