Real-World Electric Bus Operation in
Cold Weather Climates
John Carney
General Manager
Central Mass Transit Management
A First Transit Property Serving the Worcester Regional
Transit Authority
WRTA
Boston Accent: Not Just Dropping the
“R”
Town of Leominster
How you think it’s pronounced: Leo-min-stir
How it’s actually pronounced: Lemon-stir
Town of Gloucester
How you think it’s pronounced: Glow-sess-ter
How it’s actually pronounced: Glaw-stir
Town of Haverhill
How you think it’s pronounced: Haver Hill
How it’s actually pronounced: Hav rill
City of Worcester
How you think it’s pronounced: Wore-chess-tur
How it’s actually pronounced: Wuss-tur
Prior Particpation in Advanced
Technology
• Howard Ross Battery Powered Bus MBTA
• NANO Fuel MIT/ Capital Venture MBTA
• Advanced Vehicle Systems AVS/Solectria Battery
Powered Buses
Paul Revere
• Proterra Electric Bus
WRTA
WRTA Proterra Timeline
•
Union Station Hub Opened June 1st 2013
•
Six 35’ Proterra Bus delivered August – December 2013
•
Expedited Introduction of Buses Due
To Severe Service Delays
•
Charger Failed During Severe Cold &
Snow Conditions 2013/2014
Partnership between WRTA and Proterra Allowed
Full Service During Harsh Winter
• WRTA buses parked indoors overnight, including diesel & hybrid
– Reduced need for pre-heating of cabin
• Overhead charging system heated for winter performance:
– Retrofit system to prevent snow/ice buildup on the bus docking
components. Air Dryer
– Charge Head Heaters Installed in October of 2014
– Roof Scoop Heaters Installed in December/January 2014/2015
Extraordinary Engineering
Manually Operated
Winter 2014-15 in Massachusetts
• Worcester records:
– February temperature:
average 14˚F
– Minimum temperature: -6˚F
– Total snowfall: 115.6 inches
– Length of time below 40˚F:
39 days
Source: USA Today 03/05/2015
• First multiple-day closure
in WRTA history
Source: CBS Boston 02/27/2015
Worcester Winter 2014/2015
Average Annual Snowfall
#1 Syracuse, NY
126.3”
#2 Erie, PA
100.8”
#3 Rochester, NY
100.5”
#4 Buffalo, NY
96.1”
#5
#6
Snowfall Winter 0f 2014-2015
Worcester, MA
115.6”
Syracuse, NY
114.2”
Lowell, MA
113.6”
Buffalo, NY
108.8”
Boston, MA
105.7”
Erie, PA
103.8”
Rochester, NY
95.1”
WRTA Electric Bus Winter 2015 Driving
• Total Mileage 12/21 to 3/21:
27,103
• Average MPG equivalent: 12.3
– Energy efficiency due to running the
HVAC longer to achieve a
comfortable cabin temperature
• Driver comments:
– Handles well in snow
– Cabin stays warm for passengers
Energy Efficiency Winter vs Spring
• Winter all-electric energy efficiency 4X that of diesel
• No impact on time allotted for charging:
– Initial route selection provided time buffer for these situations
– Drivers on short routes can’t go around as many times without
recharging as in summer. Route allows for charging each time.
• Comparison to spring 2015 electric bus energy efficiency:
Metric
Winter
Spring
Dates
12/21/14 - 03/21/15
03/21/15 – 06/20/15
Total Miles
27,103*
31,445
MPGe average
12.3
18.2
kWh per mile
3.87
2.58
*WRTA does not operate during federal holidays.
Operational Lessons Learned
• Winter weather will impact the amount of energy used, like
with diesel. Ensure there is sufficient time for winter charging
as compared to warmer months.
• While operation can be fully maintained, its important to plan
for winter weather effects on the bus and charger.
• Although 2015/2016 winter was milder the retrofits Stood the
Test of Time
Key Presentation Take-Aways
• WRTA all-electric Proterra EcoRide buses successfully
drove in normal service during this period
• Energy efficiency depends on the season, but electric
buses still outperform diesel by 4X
• Some protective measures are needed to protect the
energy storage and charging system from extreme
conditions
Thank you!
• Thank you for your attention