NYCT Operating Experience with Hybrid Buses John P. Walsh Chief Maintenance Officer MTA New York City Transit Department of Buses November 30, 2004
Outline n Overview of NYCT Bus Operations n Hybrid Electric Bus Technology n NYCT Hybrid Bus Projects n Lessons Learned with Hybrids n Future Plans
NYCT Bus Operations n Annual Bus Customers762,190,226 n Average Weekday Ridership2,452,554 n Total Buses in Fleet 4,500 n # of Bus Routes218 n # of Bus Stops12,355 n # Of Total Employees14,388 n Annual Mileage (2003)121,255,903 n Gallons of Fuel Consumed (2003) è Diesel 44,129,685 è CNG 3,695,157
NYCT Bus Fleet *Two-stroke engines to be retired from DOB fleet by end of 2004.
The Clean Fuel Solution - Hybrid Electric n Hybrid Electric buses combine a diesel engine and electric drive components n Improved performance è Significant emissions reduction è Increased fuel economy è Smooth and quiet operation n Avoids the infrastructure costs of CNG - no special fuel handling is required
BAE/Orion VII Hybrid System Lead Acid Battery Packs Diesel Engine Generator Electric Traction Motor Power Electronics Lead-Acid Batteries Diesel Engine Generator Power Electronics (PCS) Traction Motor
NYCT Hybrid Bus Programs n Successful prototype in 1996 (Orion/GE) n Pilot fleet of 10 hybrid buses began operating in revenue service in n First production order of 125 delivered in n Second production order of 200 to be delivered in 2005.
Hybrid Revenue Service Experience n Hybrid buses in service since Sept n Approx. 700,000 revenue miles on pilot fleet to date n Approx. 800,000 revenue miles on new production fleet to date. n Drivers and customers like the buses n Brake life approximately doubled n Very positive - for a brand new technology, have exceeded expectations
Orion VII/BAE New Production Hybrid Buses - In Service Performance n First of 125 into service in February, 2004 n 100 buses in service as of November at two depot locations with different duty cycles. n Used interchangeably with standard buses n No major propulsion system problems to date n Emissions significantly better than other buses: è NOx less than half that for a clean diesel or CNG bus è CO less than one fourth that for a clean dlesel and roughly one tenth that for a CNG bus.
n The baseline fuel consumption is 2.3 MPG for 40-foot standard diesel buses n The hybrid buses have demonstrated the following fuel consumption to date: è Clara Hale Depot – 3.7 MPG è Queens Village Depot – 3.4 MPG n The hybrid bus fuel consumption is reduced approx. 40% compared to the standard diesel buses they replace. This equates to nearly 5000 gallons of diesel fuel saved per year for each bus. Orion VII/BAE New Production Hybrid Buses - In Service Performance
Orion VII Hybrid Bus
Hybrid Bus Revenue Miles
Hybrid Bus Fuel Economy (MPG)
Hybrid Bus Reliability (MDBF)
Hybrid Bus Availability % of Hybrid Fleet Availability 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Jun-99Sep-99Dec-99Mar-00Jun-00Sep-00Dec-00Mar-01Jun-01Sep-01Dec-01Mar-02Jun-02
Hybrid Emissions Results
Exhaust Pressure - DPF Inlet (PSI)
Engine Load
Orion VI Lead Acid Battery Life n For the 36 months of testing ending in February of 2004: è 17,000,000 Battery-miles, 5% replaced è Replaced batteries did not appear to be end-of- life failures è Two buses with Optima batteries in service for 40+months with no failures n Life goal of 3 years appears to be potentially achievable but not realized yet n Changes to software in Orion VII should reduce battery replacements
Battery Type Life/Cost Comparison ChemistryLead-AcidNiMHLithium-Ion Service Life (Expected) 2.5 – 4 yrs5 – 7 yrs5 – 10 yrs Cost ($ / kW-hr) $100-$150$300-$500>> $1000 Life-Cycle Cost ($/kW- hr/Yr) $25-$60$42.86-$100 >> $100 – >> $200 Lead-Acid Technology is still the cost winner … for now
Life Cycle Costs - Hybrid vs. Standard Propulsion in Transit Duty Cycle n Current differential in acquisition costs make justification of HEVs difficult n Current range differential is $ K per bus n Series HEV in NYCT high density duty cycle achieves > 35% better fuel economy than standard propulsion system n Average bus 32k/m/yr uses 13,000/gal/yr diesel annual fuel cost $26K n HEV will use 8,800 $2.00/gal annual fuel cost $17,600 - differential of $8,400/ yr n Over 12-year life minimum differential $100K n Delta will increase as cost of fuel a half life assumption of $3.00/gal the differential exceeds $125K
Life Cycle Costs - Hybrid vs. Standard Propulsion in Transit Duty Cycle
Lessons Learned - Operational n Bus operators and passengers like hybrids è Quiet, smooth operation è excellent acceleration/smooth braking è feels like a standard bus è little or no operator training required n Able to be used on all NYCT routes n Bus does not roll back on hills n More advanced troubleshooting procedures and tools required
Hybrid Bus - Future Challenges n Revise current EPA heavy duty certification protocol to allow for system evaluation. Tailpipe emissions vs. engine dyno results. è Chassis dyno testing is what is used for cars and light duty trucks. è Allows for evaluation of total system performance. è Much better representation of actual in-service performance of vehicle. è Measures the overall effects of other propulsion system components.
n Energy Storage - encourage additional development, testing, and deployment of other energy storage systems: è Advanced batteries u Lead Acid u NiMH u Sodium u Other è Ultra Capacitors è Power from grid è Solid fuels for fuel cells Hybrid Buses - Future Challenges
n Component Optimization - HEV allows for the use of other electrically driven system components. n Electric components have inherent advantges: è Remote mounting - better packaging è More efficient è High reliability index è Reduced noise signature
Hybrid Buses - Future Challenges n Opportunities for Electrically Driven Accessories: è Short term u Compressors, air and HVAC u Steering u Cooling system è Long Term u Wheel motors u ZPE operation u Fuel cell integration
Additional Information n Speaker Contact: John P. Walsh, Chief Maintenance Officer MTA New York City Transit (347) ; n Hybrid/CNG/Diesel Emissions Report n NREL Reports: reports 6369 and 6383