The report states the country could reduce gas usage and emissions by 80 percent, specifically in cars and light trucks. The goal will be “challenging” according to the report. Fuel efficiency of the conventional internal combustion engine would have to average over 180 mpg. Alternative fuels and powertrain systems would have to be considered. Each, though, had its own issues.
Says committee chair Douglas M. Chapin, “To reach the 2050 goals for reducing petroleum use and greenhouse gases, vehicles must become dramatically more efficient, regardless of how they are powered. In addition, alternative fuels to petroleum must be readily available, cost-effective and produced with low emissions of greenhouse gases. Such a transition will be costly and require several decades.”
The NRC report considered biofuel, electric vehicles, and fuel cells. Biofuel, or specifically biodiesel, would meet the 2050 goals if “lignocellulosic biomass” were used, e.g., switchgrass, wood mass, etc. A big advantage of biofuel is that they can use the current refueling infrastructure (i.e., gas stations, underground tanks, pipelines) with little change.
Electric vehicles face several distinct challenges. On the one side, EVs have a short range and long recharge times. Batteries are costly, further discouraging to consumers. On the other side, power plants generating the electricity to charge EVs would have to be remodeled to reduce emissions from their use of fossil fuels like coal.
Fuel cells, which derive their power from combining hydrogen and oxygen, do not have the range limitations of EVs nor the refueling time lag. However, the creation of hydrogen emits greenhouse gases. Fuel transport and refueling stations would have to be built.
Compressed natural gas, or CNG, was also considered in the report. Greenhouse gas emissions of CNG, though, was deemed too high to meet the 2050 figures.
Other issues considered include the high costs to consumers of many of these cleaner vehicles as well as limited availability of certain body styles like electric light trucks. Also, the report warned there is great uncertainty that many of the recommended technologies will be both powerful, clean, and economical enough to be accepted by consumers. The NRC’s conclusion is research in all technologies be supported. Policies, adds the report, reaching the level of law should wait until their full impact is properly evaluated.