Life Cycle Inventory Energy Consumption and Emissions for Biodiesel versus Petroleum Diesel Fueled Construction Vehicles

摘要

Substitution of soy-based biodiesel fuels for petroleum diesel will alter life cycle emissions for construction vehicles. A life cycle inventory was used to estimate fuel cycle energy consumption and emissions of selected pollutants and greenhouse gases. Real-world measurements using a portable emission measurement system (PEMS) were made for five backhoes, four front-end loaders, and six motor graders on both fuels from which fuel consumption and tailpipe emission factors of CO, HC, NO_x, and PM were estimated. Life cycle fossil energy reductions are estimated at 9% for B20 and 42% for B100 versus petroleum diesel based on the current national energy mix. Fuel cycle emissions will contribute a larger share of total life cycle emissions as new engines enter the in-use fleet The average differences in life cycle emissions for B20 versus diesel are: 3.5% higher for NO_x; 11.8% lower for PM, 1.6% higher for HC, and 4.1% lower for CO. Local urban tailpipe emissions are estimated to be 24% lower for HC, 20% lower for CO, 17% lower for PM, and 0.9% lower for N0_x. Thus, there are environmental trade-offs such as for rural vs urban areas. The key sources of uncertainty in the B20 LCI are vehicle emission factors.