FIGURE 6.33 Greenhouse gas emissions for Case 4 (combination of HFCVs, efficiency, and biofuels).

FIGURE 6.34 Cumulative reduction of greenhouse gas emissions for Case 2, Case 3 plus Case 2, and Case 4.

CONCLUSION: In the judgment of the committee, the maximum practicable number of HFCVs that could be on the road by 2020 is around 2 million. Subsequently, this number could grow rapidly to as many as 60 million by 2035 and more than 200 million by midcentury, but such rapid and widespread deployment will require continued technical success, cost reductions from volume production, and government policies to sustain the introduction of HFCVs into the market during the transition period needed for technical progress.

CONCLUSION: While it will take several decades for HFCVs to have major impact, under the maximum practicable scenario fuel cell vehicles would lead to significant reductions in oil consumption and also significant reductions in CO₂ emissions if national policies are enacted to restrict CO₂ emissions from central hydrogen production plants.

CONCLUSION: The unit costs of fuel cell vehicles and hydrogen in the Hydrogen Success scenario—the maximum practicable case—decline rapidly with increasing vehicle production, and by 2023 the cost premium for HFCVs relative to conventional gasoline vehicles is projected to be fully offset by the savings in fuel cost over the life of the vehicle relative to a reference case based on the EIA high-oil-price scenario. At that point, according to the committee’s analysis, HFCVs become economically competitive in the marketplace.

Fully implementing the maximum practicable hydrogen case by 2050 would require construction of approximately 80,000 on-site distributed natural gas reforming units, 80 coal gasification plants of 500 MW (electrical equivalent) with CCS, 130 biomass gasification plants (each 100 MW equivalent) with associated biomass growth and collection farms, and roughly 80,000 miles of pipelines for hydrogen supply and CCS. The committee estimates that more than $400 billion would be required to fully build out hydrogen supply to fuel the HFCVs by 2050.

The committee’s analysis indicates that at least two alternatives to HFCVs—advanced conventional vehicles and biofuels—have the potential to provide significant reductions in projected oil imports and CO₂ emissions. However, the rate of growth of benefits from each of these two measures slows after two or three decades, toward the end of the committee’s analysis period, while the growth rate of projected benefits from fuel cell vehicles is still increasing. The deepest cuts in oil use and CO₂ emissions after about 2040 would be from hydrogen.

Over the next 20 years, the greatest impact on U.S. oil and CO₂ reductions would result from implementing existing