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The most attractive non-fossil fuel for the USA-Canadian light duty transportation fleet is ethanol produced domestically from lignocellulosic agricultural feedstocks and residues. Ideally, this fuel can be produced sustainably without using any fossil fuels and without any net carbon dioxide emissions. Growing switchgrass or hybrid trees and using agricultural wastes, such as rice straw, bagasse, and corn stover, holds the potential for transforming the economies of the countries. Well-crafted programs could increase farm income, generate foreign exchange/export earnings, and result in a host of sociologic benefits, while improving environmental quality and sustainability. Five primary drivers would make a biomass ethanol industry attractive: a high petroleum price, energy security concerns, stringent greenhouse gas emissions limitations, an increase in CAFE applying to petroleum products, and a large demand for oxygenated fuels together with banning MTBE.

Hybrid electric vehicles (HEV) and other advanced propulsion technologies offer greater fuel economy and lower pollutant and tailpipe emissions. Some experts regard the HEV technology as a practical, attractive solution to social concerns about fuel economy (and related fossil fuel conservation) and vehicle emissions. [Maples 98] The technology is practical; however, an HEV is more expensive to produce than a conventional internal combustion engine (ICE). In a world of limited resources and many petroleum users and emissions sources, the policy question is whether the best use of resources is to build HEV, to improve the fuel economy and lower emissions from other sources, or to devote the resources to other environmental projects. We compare the second generation (designed for the United States) Toyota Prius, to the conventional internal combustion engine Toyota Corolla.

Ethanol from biomass (trees and grasses) can provide a significant proportion of the fuel for the light duty fleet, alleviating concerns about volatile prices, energy dependence, and global warming. We examine the costs and quantity of ethanol that can be produced from corn and biomass, as well as infrastructure issues associated with transporting and retailing ethanol for blending in gasoline. Large, but feasible, amounts of land and investment are required. Large-scale production is unlikely to occur until biomass ethanol becomes cheaper than gasoline or is mandated by regulation of gasoline fuel economy or carbon dioxide emissions.

We analyze alternative fuel/engine internal combustion engine and electric technology options that will be available over the next two decades for powering a large proportion of the U.S. light duty fleet (cars and light trucks). Lifetime private (vehicle, battery replacement and fuel) and social (externalities associated with pollutant and greenhouse gas emissions) costs for the vehicle options are estimated and compared to those of a baseline gasoline fueled internal combustion engine automobile. Technological advances continue to improve the efficiency and environmental performance of low sulfur reformulated gasoline fueled internal combustion engine automobiles. In our judgment, two fuels which may challenge gasoline for use in internal combustion engines are compressed natural gas and biomass ethanol. Compressed natural gas would lower our dependence on foreign energy supplies, would result in lower greenhouse gas emissions, and is cleaner burning than petroleum fuels.

We compare the life cycle inventories of near–term fuel–propulsion technologies. We analyze fossil fuels (conventional and reformulated gasolines, low sulfur diesel, and compressed natural gas (CNG)), ethanol from biomass, and electricity, together with internal combustion engines (port and direct injection, spark and compression ignited) and electric vehicles (battery–powered, hybrid electric, and fuel cell). The fuel economy and emissions of conventional internal combustion engines powered by gasoline continue to improve. Unless emissions of pollutants and greenhouse gases (GHG) are stringently regulated or gasoline prices more than double, gasoline powered internal combustion engines will continue to dominate the light duty fleet. Two appealing alternative fuels are CNG and biomass ethanol. CNG cars have low emissions, including GHG and the fuel is less expensive than gasoline. Biomass ethanol can be renewable and have no net carbon dioxide (CO2) emissions.

We present a life cycle assessment of producing automobiles using the Environmental-Input-Output analysis tool (EIO-LCA). The tool is based on the 1987 U.S. 519 sector input-output table. Appended to the table are more recent data on energy usage and environmental discharges for each sector. All of the data, from the input-output matrix to the energy use and environmental discharges are U.S. government data and are publicly available. The EIO-LCA tool allows us to estimate all of the energy use and environmental discharges associated with making cars, not just that associated with automobile manufacturers. In contrast to the SETAC-EPA life cycle analysis tool, there is no need to draw an arbitrary boundary for the analysis or to engage in an expensive, time consuming effort to gather data on energy use and environmental discharges from each plant. In addition, the data are not confidential.