This report includes results of an evaluation of the operation of new compressed natural gas (CNG) and diesel hybrid electric buses from Orion Bus Industries (model Orion VII buses) operating at New York City Transit (NYCT). This evaluation is part of a series of evaluations from the U.S. Department of Energy (DOE). DOE, through the National Renewable Energy Laboratory (NREL), has been tracking and evaluating new propulsion systems in transit buses and trucks for more than 10 years with an established and documented evaluation protocol1.
DOE/NREL evaluated the original 10 prototype diesel hybrid buses from Orion and BAE Systems and operated at NYCT (model Orion VI buses). Results from that evaluation2 were published in July 2002 and provided information on the prototype buses from 1998 through 2001. NYCT worked with Orion and BAE Systems to develop, implement, and test hybrid propulsion buses in an attempt to reduce emissions and operating costs and increase fuel economy.
NYCT’s Clean Bus Program was created in 1992 to lower bus fleet emissions. In 2000, NYCT established a policy of only purchasing low emission buses for new bus orders. This policy, coupled with NYCT’s desire to achieve the best fuel economy, has resulted in NYCT’s recent purchase order for hybrid buses. The NYCT Clean Bus Program currently includes several activities:
Use of CNG buses
Replacement of the oldest diesel engines (two-stroke) with newer low emissions engines (Detroit Diesel Series 50 exhaust gas recirculation engines)
Use of ultra low sulfur diesel fuel for all diesel equipment (starting in 1998 with less than 30 parts per million (ppm) sulfur, expected to be less than 15 ppm starting in 2006)
Addition of diesel particulate filters (DPF) to the existing and new diesel engines
Use of hybrid propulsion buses with engines equipped with DPFs
Hybrid technology has generally been tested at NYCT in an effort to explore options other than CNG technology. This is because not all of NYCT’s operating depots are cost-effective candidates for CNG infrastructure due to space constraints inside buildings and the proximity of neighboring buildings. In early 2000, NYCT ordered 260 CNG buses in two orders from Orion Bus Industries (order one was 125 buses, order two was 135 buses). At the same time, NYCT made a commitment to purchase two orders of buses with the BAE Systems hybrid propulsion system from Orion Bus Industries. One order was for 125 buses, the other for 200 buses.
1 General Evaluation Plan, Fleet Test & Evaluation Projects, July 2002, NREL, NREL/BR-540-32392, www.nrel.gov/vehiclesandfuels/fleettest/pdfs/32392.pdf.
2 NYCT Diesel Hybrid-Electric Buses, July 2002, NREL, NREL/BR-540-32427 www.eere.energy.gov/afdc/pdfs/nyct_diesel_hybrid_final.pdf.