Sustainable Transportation Energy Pathways (STEPS)
Parker, Nathan C., Bryan M. Jenkins, Peter Dempster, Brendan Higgins, Joan M. Ogden (2011) "The Biofuels Pathway" chapter 1 in Sustainable Transportation Energy Pathways: A Research Summary for Decision Makers. Institute of Transportation Studies, University of California, Davis, 15 - 37
Biofuels have been seen as the nearest-term answer to the need for alternatives to petroleum fuels in the transportation sector. Despite recent debate over life-cycle environmental impacts and potential food-sector impacts, much interest remains in the expansion of biofuel production capacity to displace petroleum and provide low-carbon fuels—especially for heavy transport and aviation, where few other sustainable alternatives to liquid fuels exist. Besides, biofuels (and bioenergy production more generally, including heat and power applications) offer opportunities for economic development, diversification of the farm sector, integration of forest management, and diversion of urban wastes from landfills.
But these opportunities come with substantial challenges. With the current state of technology, the lowest-cost biofuels do not provide major environmental benefits, while the biofuels that are expected to provide significant benefits are not yet commercially viable. Resources for the United States have been estimated to be sufficient to produce enough biofuel to meet roughly a third of the nation’s transportation fuel demand, but large uncertainties are associated with these estimates and sustainability of production and manufacturing processes is not yet fully understood. Additionally, best uses for biomass—whether to produce the liquid biofuels discussed in this chapter, to generate electricity for electric vehicles, to produce hydrogen for fuel cell vehicles, or to be used in other sectors—are still to be sorted out through technology innovation and market action.
This chapter discusses some of the major questions regarding future use of biofuels in the transportation sector and highlights STEPS research on these issues. What is the technical outlook for advanced biofuel production technologies?
• To what extent can biofuels contribute to future transportation fuel supply? What are the constraints on feedstock for those biofuels? Where is advanced biofuels production likely to take place in the United States?
• How compatible are biofuels with existing vehicles and infrastructure?
• What are the environmental impacts of biofuels compared to alternatives? How do we measure sustainability for biofuels?
• What policies and business strategies are needed to support biofuels in both the near and long term?