and will probably be sited in regions near coal and biomass supplies, and so buildout rates will be lower than those for the cellulosic-ethanol plants discussed above. The panel estimates that at a growth rate of 20 percent until 2035, 2.5 million barrels of gasoline equivalent would be produced per day in combined coal and biomass plants. Production at that level would consume about 300 million dry tons of biomass—less than the projected biomass availability—and about 250 million tons of coal per year.

Because of the vast coal resources in the United States, the actual supply of coal-to-liquid fuel will be limited not by feedstock availability but rather by market penetration. At a build rate of two to three plants per year, up to 3 million barrels of gasoline equivalent could be produced per day by 2035. Production at that level would consume about 580 million tons of coal per year. However, issues related to an increase in coal mining by 50 percent need to be considered. At a build rate of three plants starting up per year, five to six plants would be under construction at any time.

COSTS, BARRIERS, AND DEPLOYMENT

Production of alternative liquid transportation fuels from coal and biomass with technology commercially deployable by 2020 can play an important role in reducing U.S. oil consumption and greenhouse gas emissions. The various options have different greenhouse gas impacts, and the choices will most likely depend on U.S. carbon policy. The panel used a consistent set of assumptions to estimate the costs of cellulosic ethanol, coal-to-liquid fuels with and without geologic CO2 storage, and coal-and-biomass-to-liquid fuels with and without geologic CO2 storage (see Table Sy.1). Although the estimates do not represent predictions of prices, they allow comparisons of fuel costs relative to each other. Coal-to-liquid fuels with geologic CO2 storage can be produced at a cost of $70/bbl of gasoline equivalent and thus are competitive with a $75/bbl gasoline equivalent. The costs of fuels produced from biomass without geologic CO2 storage are competitive with a $115/bbl gasoline equivalent with biochemical conversion and a $140/bbl gasoline equivalent with thermochemical conversion. The costs of cellulosic ethanol and coal-and-biomass-to-liquid fuels with geologic CO2 storage become more attractive if a CO2-equivalent price of $50/tonne is included.

Attaining supplies of 1.7 million barrels of biofuels per day, 2.5 million barrels of coal-and-biomass-to-liquid fuels per day, or 3 million barrels of coal-



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