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The New York State Energy Research and Development Authority (NYSERDA), under its Alternative Fuels for Vehicles Fleet Demonstration Program (AFV-FDP), monitored the operation of 31 compressed natural gas (CNG) transit buses divided among five transit properties in New York State. The CNG buses were delivered in 1992 and have accumulated over 3.73 million kilometers (2.32 million miles) of operation through September 1995. Data collected included fuel consumption, maintenance histories, acceleration, driveability, and emissions. Several of these buses experienced problems with defective pressure relief valves though no accidents resulted from these failures. During the period of operation, various upgrades and learning experiences have contributed to improved operations and lower emissions, though variations in emissions were observed due to drift in fuel system calibration.

Fuel cell power plants offer several advantages over conventional internal combustion engine (ICE) and battery power plants for public transport vehicles. Higher efficiencies and lower pollutant emissions can be realized along with long life, low maintenance and quick refueling. Fuel cells can operate from a variety of fuels such as methanol, methane, or pure hydrogen. The main disadvantages are the required higher capital outlays and the slower response times compared to ICE- or battery powered vehicles. By combining a suitable battery in a hybrid configuration, the current generation phosphoric acid fuel cell (PAFC) is already practical for meeting the operational needs of transit buses. An advanced design for a small urban transit bus has been developed under a contract with the U.S. Department of Energy. Design and packaging considerations along with performance projections will be presented and compared with diesel transit buses in this paper.