School bus program: transition to alternative fuels

摘要

The California School Bus Program is the largest alternative fuel bus program in the nation. It has been in existence for over five years and has gathered data on alternative fuel bus operations, maintenance, emissions, engine performance and cost. To date, there have been approximately 787 advanced technology and alternatively-fueled buses purchased through this program. The program has been developed in three five-year phases allowing manufacturers to further develop commercially-available alternative fuel technologies between phases. Methanol, compressed natural gas (CNG) and advanced diesel technology have been used to power buses in the first two phases. This paper compares alternative fuel types in a real-world environment. The development of methanol and CNG fueling station infrastructure and fuel cost comparisons are discussed. During the development of alternative fuel school buses, safety technology is discussed. Emissions testing has been required for engine manufacturers to meet California Air Resources Board (CARB) emissions standards for each phase of the program. Phase three will add electric buses to the program and this paper discusses the development of electric bus technology. Distance, performance, cost, battery technology and electric school bus design specifications are discussed. The intent of this paper is to provide fleet managers, and others, with information on the choices in using alternative fuel buses.