Even with Reinventing Fire’s 2050 outlook on oil use, the nation will still need 3.1 million bbl/d of liquid fuel (minus any natural gas used in trucks). While they can't be cost-effectively electrified, planes and heavy trucks can run on second and third generation biofuels. Unlike first generation fuels, second generation biofuel feedstocks do not generally compete with food cropland, and they exhibit higher conversion efficiencies. In addition, such cellulosic biofuels can run existing vehicles with no engine or infrastructure modifications. Our analysis shows that cellulosic biofuels can be produced in sufficient supply at costs below $80/barrel oil equivalent. Furthermore, a number of firms are investing in algal fuels (not shown here) given their potential for a major leap in biofuel productivity. That's not to say algal fuels will proliferate overnight. As with next generation Revolutionary+ fuel-cell autos, hydrogen-powered trucks, and advanced plane designs, growing and processing algae face significant technology challenges at every step. But they are receiving considerable talent and investment. For more, see Biomass process flow for advanced cellulosic ethanol process.
A: Thomas G Kreutz, et al. 2008. Fischer-Tropsch Fuels from Coal and Biomass. Princeton Environmental Institute. link
A (part 2): U.S. Energy Information Administration. 2010. U.S. EIA Assumptions to the Annual Energy Outlook 2010: Petroleum Market Module. U.S. Energy Information Administration. link
B: Bain, R.L. 2007. "World Biofuels Assessment: Worldwide Biomass Potential Technology Characterizations." National Renewable Energy Laboratory. link
B (part 2):U.S. Energy Information Administration. 2010. U.S. EIA Assumptions to the Annual Energy Outlook 2010: Petroleum Market Module. U.S. Energy Information Administration. link