Full Fuel Cycle Energy,Greenhouse Gas and Pollutant Burdens of Ethanol/Diesel Blended Fuels:Implications for the Renewables Market and Petroleum Displacement Goals

摘要

Bench experiments and fleet demonstrations have been conducted in recent years in the U.S.and abroad using emulsified blends of ethanol(CH3CH2OH)and diesel fuel,so called E-diesel,in compression ignition(CI)engines for light-and heavy-duty vehicular application.In the U.S,the market for E-diesel that emerges over the next five to ten years will very likely be concentrated in subsets of the heavy vehicle fleet.Thus,the present study of the energy,greenhouse gas and emission effects of E-diesel relative to straight petroleum diesel focuses on urban transit buses and farming tractors,likely to be among the earliest commercial E-diesel applications.Demonstration programs in the U.S.have featured buses and farming tractors operating on E-diesel blends of up to 15 percent by volume(3.9% and 5.7% oxygen by weight,respectively).Analysts at Argonne National Laboratory(ANL)applied an upgraded version of the Greenhouse gases,Regulated Emissions,and Energy use in Transportation(GREET)full fuel cycle model to estimate energy use and emissions associated with ethanol/diesel blend fuel on a per-mile(or per operation-hour),per-vehicle basis.All energy-consuming facets of the fuel and feedstock production processes are explicitly incorporated in the"upstream"calculation for ethanol,diesel,and emulsifier additive blend components.Results of the analysis identify the key factors distinguishing energy and petroleum demands of E-diesel blends versus(heating-value equivalent)pure diesel fuels and whether significant or measurable net energy and emission benefits may be expected from E-blends for the scenarios considered.