The process also offers potential advantages over producing liquid fuels from coal using conventional methods, which emit carbon dioxide. Because H2CAR would not emit this additional carbon dioxide, the process would eliminate the need for proposed carbon dioxide "sequestering."
Sequestering would involve pumping carbon dioxide emissions into saltwater aquifers and hollow underground pockets that used to contain oil, natural gas and coal deposits. But the procedure poses several potential pitfalls.
"Clearly, massive quantities of carbon dioxide would be sequestered during a century-long production of liquid fuels from coal," Agrawal aid. "This would place extreme demands on the carbon dioxide capture, storage and monitoring systems."
The new process also would be more practical than all-electric or hydrogen-powered cars, in part because of the limited storage capacity of batteries and hydrogen storage tanks.
"The tremendous convenience provided by the existing infrastructure for delivering and storing today's fuels is a huge deterrent to introducing technologies that use only batteries or hydrogen alone," Agrawal said. "A major advantage of our process is that it would enable us to use the current infrastructure and internal combustion engine technology. It is quite attractive for hybrid electric vehicles and plug-in hybrid electric vehicles."
To grow enough biomass for the entire nation's transportation needs using the conventional method for producing biofuels would require a land area 25 percent to 55 percent the size of the United States, compared with about 6 percent to 10 percent for the H2CAR process.
"This large reduction of land area needed for H2CAR provides an opportunity for sustainable production of hydrocarbon fuel for the foreseeable future," Agrawal said.
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