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Electric School Buses
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Exploring Electric Buses for MPS

Exploring Electric Buses for MPS

There is interest within the Minneapolis Public Schools community to include electric school buses in our fleet of vehicles in an effort to further reduce greenhouse gas emissions and lessen the impacts of tailpipe pollutants on children’s health.

 

Minnesota Pollution Control Agency (MPCA) has previously offered grants to businesses, communities and organizations to help fund purchases of new electric or ‘clean diesel’ vehicles. The most recent grant offered a total of $630,000 statewide for six electric school buses. An additional $5,000 was also available for the supporting electric vehicle charging station. The funding was divided between out state and the metro area. For the metro area, 60% of the grant funds were available, or $378,000, or 4 buses.

MPS Transportation Services studied the requirements of the MPCA grant as well as the potential costs and operational changes associated with incorporating electric school buses into its fleet. Despite not qualifying for this particular grant due to the model year requirement, there are other factors to consider in the conversation of including electric school buses in our fleet.

  • Vehicle Cost: The current cost of electric school buses and charging stations is prohibitively expensive to implement. Electric school buses are almost triple the cost of traditional propane or diesel school buses. An electric school bus can cost $350,000, compared to $85,000 to $100,000 for a conventional fuel bus.
  • Charging Station Costs: There is also an investment needed to purchase and install charging stations, of which the grant provides $5,000 for these expenses. The cost of the charging station is dependent on the type of electric bus and the required rate of charging. While researching electric vehicles we have received quotes for charging stations at $80,000 per vehicle, plus an additional $80,000 to install the charging station, for a total of an additional $160,000 per electric school bus.
  • Vehicle Range: The advertised range of electric buses of 120 miles, under ideal conditions, would not be sufficient for the length of our transportation day, which stretches from 6 AM to after 7 PM most school days,  with minimal opportunities to re-charge midday.
  • Cold Weather Impact: Cold weather and the heating system within the bus reduce the battery charge in the bus, decreasing the distance a school bus can drive in colder months. In 2017 the Massachusetts Department of Energy Resources (DOER) completed a pilot project to test electric school buses in school transportation operations in cold climates. Findings from the Electric School Bus Pilot Project Evaluation report echo similar concerns of Minneapolis Public Schools’ Transportation department. The decrease to the battery charge would severely impact bus operations and efficiencies.
  • Additional Driver Requirements: Electric school buses are not currently available without air brakes, which require school bus drivers to obtain an air brake endorsement – in addition to their CDL license with school bus endorsement and passenger endorsement. Large vehicles with air brakes take special knowledge, training and experience to operate safely.
  • Increased Maintenance Needs: School buses with air brakes were purposely removed from our fleet due to their high maintenance needs. Adding air brake vehicles back into our fleet could increase vehicle down time and refocus our mechanics’ maintenance duties. An important finding from the Electric School Bus Pilot Project Evaluation report was that the electric buses were out of service for a relatively high number of days and ultimately logged fewer than half as many miles as the average diesel bus. This was due in part to a lack of experienced, on-the-ground technical assistance.

 

Until we are comfortable that electric buses will meet our needs, Transportation Services will continue to move our fleet to propane powered units which have proven to be dependable, economical and clean running. The switch from diesel fueled school buses to propane school buses began in 2014 with a state grant to offset the cost of propane fuel for the first year of implementation. Currently, there are 66 propane vehicles in the fleet.

  • Safety: Propane school buses operate quieter than diesel powered buses improving safety on the road.
  • Cost: Propane school buses have the lowest total cost-of-ownership available, allowing MPS to use those savings throughout the district.
  • Clean Fuel: In real-world testing conducted by West Virginia University in 2018, propane buses produced 96% fewer NOx[1] emissions compared with clean diesel buses. 

In accordance with Minnesota State statute, Transportation Services has also developed idling restrictions for all vehicles to address unnecessary negative impacts to air quality and vehicle noise.

Transportation Services has developed a cycle of replacement methodology used to identify vehicles targeted for replacement. This methodology consists of key categories and a weighting system for each. Yearly, vehicles are evaluated for replacement using this methodology. Buses that score the lowest are budgeted for replacement. Using this system, Transportation Services is better able to predict replacements and plan more effectively. As buses are being replaced, they have been replaced with propane vehicles, which are less expensive to operate, maintain and repair and meets EPA Clean Air requirements.

Below is the rubric used to determine which buses to replace:

Category

Ranking

Access value

Age

Maximum weight: 40

Less than 10 years

40

11

30

12

20

13

10

14 and over

0

Repair trend over last 2 years

Maximum weight: 20

Under $5k

20

$5k - $10k

10

Over $10k

0

Mileage

Maximum weight: 20

Under 100k

20

101k – 150k

10

Over 150k

0

Interior condition

Maximum weight: 10

Good

10

Poor

0

Exterior condition

Maximum weight: 10

Good

10

Poor

0

 

Minneapolis Public Schools has 176 buses in its fleet with an average vehicle age of 5 years. Below is a brief breakdown of our current fleet.

Size

Fuel Type

Quantity

Total Quantity

Average age

Average mileage

Full-size bus, type “C”

Diesel

45

74

 

2012

91,928

Propane

29

2019

19,110

Seat belt ready, type “C”

Diesel

9

13

2012

105,841

Propane

4

2020

7,558

Wheelchair bus

Diesel

17

56

2012

93,888

Propane

33

2019

21,572

Unleaded

6

2018

29,431

Small bus, type “A”

Unleaded

21

21

2015

66,287

Type III vehicles

Unleaded

12

12

2016

54,601

 

Full-sized buses have 71-seat capacity (elementary students) Standard, large school bus.

Seat belt ready buses have reinforced seats so infant car seats can be installed. They have 65-seat capacity and look like standard, large school buses. In 2018, MPS began to specify seat belt ready buses when ordering replacement vehicles. These buses are constructed with reinforced floors to accommodate seat belts.

Wheelchair buses range from 10-seat to 50-seat capacity, with 2, 3 or 6 wheelchair capacities. Size ranges from small to large buses.

Small buses look like buses typically associated with special needs transportation but do not have wheelchair capacity.

Type III vehicles are white vans with 6-seat or 8-seat capacity. Four vans have 1 wheelchair capacity.

 

 

 

 

 

 

 



[1] NOx is a generic term for the nitrogen oxides that are most relevant for air pollution, namely nitric oxide (NO) and nitrogen dioxide (NO2)