A hybrid hydrogen-carbon (H ₂ CAR) process for the production of liquid hydrocarbon fuels is proposed wherein biomass is the carbon source and hydrogen is supplied from carbon-free energy. To implement this concept, a process has been designed to co-feed a biomass gasifier with H ₂ and CO ₂ recycled from the H ₂ -CO to liquid conversion reactor. Modeling of this biomass to liquids process has identified several major advantages of the H ₂ CAR process. ( i ) The land area needed to grow the biomass is <40% of that needed by other routes that solely use biomass to support the entire transportation sector. ( ii ) Whereas the literature estimates known processes to be able to produce ≈30% of the United States transportation fuel from the annual biomass of 1.366 billion tons, the H ₂ CAR process shows the potential to supply the entire United States transportation sector from that quantity of biomass. ( iii ) The synthesized liquid provides H ₂ storage in an open loop system. ( iv ) Reduction to practice of the H ₂ CAR route has the potential to provide the transportation sector for the foreseeable future, using the existing infrastructure. The rationale of using H ₂ in the H ₂ CAR process is explained by the significantly higher annualized average solar energy conversion efficiency for hydrogen generation versus that for biomass growth. For coal to liquids, the advantage of H ₂ CAR is that there is no additional CO ₂ release to the atmosphere due to the replacement of petroleum with coal, thus eliminating the need to sequester CO ₂ .