Two other alternative technologies that are likely to contribute to improved U.S. fuel economy are electric vehicles, including plug-in hybrid electric vehicles (PHEVs), and diesel engines in light-duty vehicles. However, these options were not explicitly evaluated by the committee, both because of resource limitations and because uncertainties in the future costs and consumer acceptance of these technologies were judged to be too great for the committee to have confidence in any assumed penetration rates. For all technologies, the study was restricted to light-duty vehicles (automobiles and light trucks), which represent the bulk of the U.S. vehicle market.

As a benchmark for evaluating the ability of HFCVs and other technologies to reduce oil imports and CO2 emissions, the committee developed a reference case scenario based on the high-price case of the Energy Information Administration’s (EIA’s) Annual Energy Outlook 2008 (EIA, 2008). This scenario included a significant increase in fuel economy standards as required by the Energy Independence and Security Act of 2007. The committee used the EIA report to estimate factors such as the future number of vehicles of different types on the road, as well as reference case fuel economies and gasoline prices. The committee recognizes, of course, that the projections presented in this study—like any other—contain significant uncertainties and unknowns because of changes that are likely to occur over the next several decades.


The substantial financial commitments and technical progress made by the automotive industry, private entrepreneurs, and the U.S. Department of Energy (DOE) in hydrogen fuel cell and hydrogen production technologies suggest the potential for progress to the point that commercial HFCVs could be introduced in the United States in 2015-2020. However, these vehicles are unlikely to be cost-competitive until several years after 2020 even if the maximum practicable number is reached. It will thus require substantial government action (e.g., subsidies and enactment of regulations), plus continued support for research, development, and demonstration (RD&D), to move HFCVs into the market in sufficient numbers to reduce costs and make the technology self-supporting in the marketplace. Nevertheless, the committee’s analysis also showed that the long-term promise of HFCVs in reducing oil consumption and CO2 emissions is significant, and potentially greater than that of other nearer-term alternatives. Although it was not asked to make a formal analysis of the value of policies to support hydrogen, the committee believes that, in view of the potential risks posed by oil supply disruptions and increasing CO2 emissions from oil use, the magnitude of the potential benefits justifies sustained government support of hydrogen vehicle development as part of a portfolio of options to address these serious national problems.

The committee’s analysis indicated that over the next two decades, a combination of improved conventional and hybrid vehicle fuel economy, together with increased use of biomass-derived fuels (known generically as biofuels)—and with sufficient market conditions and policies in place—could deliver substantial reductions in U.S. oil use and CO2 emissions. While HFCVs are unlikely to deliver significant benefits in this period, eventually they can do much better. Thus HFCVs are not direct competitors with other options that are able to deliver more immediate environmental and fuel use benefits. Instead, if employed with these options, collectively they can achieve dramatic, long-term reductions in oil use and CO2 emissions—benefits that could continue to grow beyond the 2030-2050 time frame. Achieving significant benefits of this kind, however, will require additional policy measures to promote the early introduction of fuel cell vehicles and to ensure that hydrogen is produced in ways that do not add to the CO2 burden.

CONCLUSION 1: A portfolio of technologies including hydrogen fuel cell vehicles, improved efficiency of conventional vehicles, hybrids, and use of biofuels—in conjunction with required new policy drivers—has the potential to nearly eliminate gasoline use in light-duty vehicles by the middle of this century, while reducing fleet greenhouse gas emissions to less than 20 percent of current levels. This portfolio approach provides a hedge against potential shortfalls in any one technological approach and improves the probability that the United States can meet its energy and environmental goals. Other technologies also may hold promise as part of a portfolio, but further study is required to assess their potential impacts. See Chapter 9.

CONCLUSION 2: Sustained, substantial, and aggressive energy security and environmental policy interventions will be needed to ensure marketplace success for oil-saving and greenhouse-gas-reducing technologies, including hydrogen fuel cell vehicles. See Chapter 8.


To develop the maximum practicable number scenario and associated budget roadmap, the committee assessed the technical progress and future challenges for (1) hydrogen fuel cell vehicles and (2) hydrogen production and delivery systems.

Hydrogen Fuel Cell Vehicles

Concentrated efforts by private companies, together with the U.S. FreedomCAR Fuel Partnership (FCFP) and other government-supported programs around the world, have resulted in significant progress toward a commercially viable hydrogen fuel cell vehicle since the publication in

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