One of the possible configurations of the proposed H2CAR process. Some images courtesy of Department of Energy/National Renewable Energy Laboratory. Clearly it would be best if coal was not used but biomass only.
Scientists have demonstrated that a hybrid system of hydrogen and carbon can produce a sufficient amount of liquid hydrocarbon fuels to power the entire U.S. transportation sector. Using biomass to produce the carbon, and solar energy or nuclear energyor wind energy to produce hydrogen, the process requires only a fraction of the land area (6-15%) needed by other proposed methods (25-58%).
The reason for significant decrease in land area requirement for the H2CAR process as compared to conventional processes is that hydrogen production from solar energy is an order of magnitude more efficient than biomass growth, which typically grows with an average energy efficiency of less than 1%.
CO2 is not waste in the H2CAR process.
If H2CAR was enabled and cars and trucks were converted to plug-in hybrids and electric vehicles then excess biomass could be used for residential and commercial power. The U.S. could even become an exporter of oil.
H2CAR and the conversion to plug-in hybrids and electrics would take a minimum of 20 to 30 years but it is a better plan than many others that have been suggested.