This report summarizes the results of a research program that assessed the technology of light-duty vehicles and fuels that could be developed and commercialized during the next 25 years. The research was done at the Massachusetts Institute of Technology from mid-2005 to mid-2008. Our objective was to assess and compare options for reducing fuel consumption, especially fuels from petroleum and greenhouse gas (GHG) emissions, during the production and use of both fuels and vehicles.
This is a successor to our 2000 report, On the Road in 2020, which addressed similar objectives. Since that report was written, the world has moved on with new vehicle and fuel technologies, and with inexorably increasing worldwide demand for all transportation services. That demand lends more urgency to curbing the growth of consumption of petroleum fuel and of GHG emissions.
Our research for the current report was confined to industrialized countries, with an emphasis on the United States but also including some western European countries. We first assessed the application of new vehicle and fuel technologies to the performance, cost, and lifecycle emissions of individual vehicles. We then considered the effects on the total on-the-road fleet of introducing those technologies using plausible assumptions about how rapidly they could be developed, manufactured, and sold to buyers to replace existing vehicles and fuels or to add to the total fleet.
We have concluded that a 3050% reduction in fuel consumption is feasible over the next 30 years. In the short-term, this will come as a result of improved gasoline and diesel engines and transmissions, gasoline hybrids, and reductions in vehicle weight and drag. If these improvements are achieved, we estimate a $1,500$4,500 increase in vehicle costs. Over the longer term, plug-in hybrids and later still, hydrogen fuel cells may enter the fleet in numbers sufficient to have significant an impact on fuel use and emissions.
Alternative fuels that replace petroleum fuels are unlikely to change GHG emissions significantly. The major near-term alternatives are based on fossil raw materials like the Canadian oil sands or coal, which increase GHG emissions. Some biofuels may prove beneficial, depending on the particular biomass feedstock and conversion technology. But the U.S. emphasis on corn-based ethanol is not obviously justifiable. It has high economic costs, questionable GHG advantages, and other unfavorable environmental impacts.
No single technology development or alternative fuel can solve the problems of growing transportation fuel use and GHG emissions. Progress must come from a comprehensive, coordinated effort to develop and market more efficient vehicles and benign fuels, and to find more sustainable ways to satisfy transportation demands.
Detailed discussions of our research conclusions and policy prescriptions can be found in the Executive Summary (pp. ES-2 to ES-11) and in Section 8 of the report (pp. 155-160).
Study Group Participants
Mechanical Engineering; MIT Joint Program on the Science and Policy of Global Change