An assessment of renewable transportation fuels and technologies

Concerns about urban air pollution, energy supply security and global warming are motivating development of alternative transportation fuels and efficient, low polluting vehicle technologies. If transportation fuels were derived from renewable sources, emissions of greenhouse gases would be largely eliminated. If these fuels were used in zero or near-zero emission vehicles now under development (battery powered or fuel cell electric vehicles), emissions of tailpipe pollutants would be eliminated as well. In this paper, the authors review the technical and economic prospects for and R and D challenges facing transportation systems based on renewable energy. The authors concentrate their assessments on several fuels (ethanol, methanol, electricity and hydrogen), which could be used with significantly reduced emissions of tailpipe pollutants and greenhouse gases, and which could be produced on a large scale from widely available renewable resources (solar, wind, biomass). Within the set of options examined, the authors find a range of technically and economically plausible scenarios leading from the present petroleum/internal combustion engine transportation system toward one based largely on one or more renewable fuels used in zero or near zero emission vehicles.