Environmental, health, and safety concerns associated with nonpetroleum fuel use in US transportation

This report qualitatively examines the environmental, health, and safety concerns associated with the use of three alternative fuels in the US transportation system: methanol, compressed natural gas, and electricity. For each of these fuels, this report presents the results of a literature review, discussions with specialists, and recent data from in-use fleet tests and summarizes the state of knowledge of their potential air pollution contribution from end use and process emissions relative to gasoline and diesel fuels. Carbon monoxide, particulate matter, ozone precursors (oxides of nitrogen and volatile organics), and carbon dioxide (from processing activities) are emphasized. Methanol-fueled vehicles are expected to have emissions comparable to their gasoline counterparts at least during the initial years, albeit with higher emissions of formaldehyde. Methanol production from coal may result in higher emissions of carbon dioxide. Compressed natural gas vehicles have the potential to reduce emissions of carbon dioxide and nonmethane hydrocarbons relative to conventional fuels. Electric vehicles using recharge power from nuclear or renewable energy sources hold the greatest promise for reduced air emissions. The manufacture and disposal of materials from lead-acid and nickel-iron batteries present safety concerns related to the potential emission of toxic materials. 69 refs., 7 figs., 8 tabs.