Conclusion and Recommendations
We must change our transportation policy if we are to address rising dependence on imported oil and greenhouse gas emissions. Avoiding serious climate change will almost certainly require a significant reduction in projected U.S. transportation greenhouse gas emissions by 2025 and a dramatic reduction in absolute emissions by 2050. Moreover, whatever strategy we used to reduce transportation carbon dioxide emissions must not interfere with our equally urgent efforts to minimize any increase in coal emissions and then to reduce those emissions.
The only plausible strategy for achieving significant reductions in projected vehicle petroleum use and carbon dioxide emissions by 2025 is fuel efficiency. For achieving 2050 targets, we believe that the most plausible strategy is a plug-in hybrid (PHEV) running on a combination of low-carbon electricity and a low-carbon biomass-derived fuel. The hydrogen fuel cell is the AFV that has the most technical and infrastructure hurdles and is the least efficient pathway for utilizing renewable resources. Given these conclusions, we have a number of recommendations: 21
Phase in CO2-related standards for cars and light trucks. We should aim for at least a 33% reduction in CO2 emissions per mile for new vehicles by 2020 (which would still leave new U.S. vehicles less efficient than European vehicles will be by 2010). Absent such standards, emissions and imports will continue to grow sharply. There is no escape from a government mandated solution, whether in the form of CO2 emissions standards or a rebate for efficient vehicles and feebate for inefficient vehicle. Absent a standard, much of the efficiency gain of new technologies will likely go towards providing increased vehicle acceleration and weight, as it has for the past two decades. Ideally, the government would adopt measures that would accelerate the market penetration of hybrids, particularly hybrid partial ZEVs, since that is the best platform for the subsequent generation of vehicles needed to achieve absolute reductions in vehicle carbon dioxide emissions by 2050.
Aggressively pursue plug-in hybrids. If PHEVs were to prove practical, they are probably the ideal future platform for addressing all three major problems created by current vehicles: greenhouse gas emissions, tailpipe emissions, and oil consumption. PHEVs would likely utilize renewable electricity resources three to four times more efficiently than hydrogen fuel cell vehicles, and have a comparably lower per mile cost of operation. Federal and state governments should launch a major R&D effort to develop PHEVs and immediately begin pilot programs to see how they operate in real-world conditions. It is particularly important to learn if economic value can be derived from electric utility services, such as spinning reserves, provided by PHEVs when they are not being driven. If so, PHEVs might have no price penalty compared to conventional vehicles. Also worth exploring is how to capture the air quality benefits from PHEVs running all-electric during ozone-alert days.
Aggressively promote biomass-derived fuel. The most plausible biofuel for delivering significant reductions in U.S. greenhouse gas emissions and oil consumption in the medium- and long-term is cellulosic ethanol. We endorse the recommendations that the Commission has received through its support of "The Role for Biomass in America's Future" Project, including
. Driving the development of the first six pioneer cellulose-to-energy plants between 2008 and 2012 using production or investment incentives;
. Modifying agricultural subsidies to include energy crops without increasing total farm subsidies or decreasing farm income; and
. Increasing and/or redirecting R&D towards biofuels.
We agree with the Project that the biofuels "effort should be at least as large as that currently underway for hydrogen." Research and development into synthetic diesel fuel made from a mixture of gasified coal and biomass should be pursued, accompanied by R&D into capturing and storing the hydrogen from this process. Ultimately, a renewable (or low-carbon) fuels standard will be beneficial, especially in helping to ensure that alternative fuels like hydrogen or synthetic diesel actually reduce greenhouse gas emissions.
Take a long-term, conservative perspective on hydrogen. While hydrogen might ultimately prove to be a viable and environmentally desirable alternative fuel post-2035, it is currently getting funding and policy attention that is vastly disproportionate to both its probability of success and likely environmental benefits. Hydrogen should be viewed as a long-term, high-risk R&D effort, requiring at least three major scientific breakthroughs (fuel cell membranes, storage, and renewable hydrogen generation) before it is practical or desirable. It is worth continuing hydrogen R&D, but at least twenty years premature to be investing substantial funds in deploying vehicles or infrastructure. The only pilots that are justified are those that feed back directly into the R&D process. For hydrogen cars to be cost-effective in reducing greenhouse gas emissions, the government will first have to sharply shift our current energy policy to make renewable power the primary source of U.S. electricity. Also, hydrogen is no alternative to government regulations; indeed, for hydrogen and fuel cell vehicles to become commercially successful, the federal government will have to intervene in the vehicle marketplace far more than it has ever done in the past.