Boston Takes Charge of Zero-Emissions Opportunity

Planning for Boston's new Battery Electric Bus (BEB) and Electric Trolleybus (ETB) fleets

Massachusetts Bay Transportation Authority (MBTA) | Boston, Massachusetts, USA | 2019-Ongoing

Minimized upgrades to existing power infrastructure through extensive analysis

BEBs have fully electric HVAC systems and charge at overhead fast-charge stations

BEBs provide significant environmental and emissions improvements for MBTA bus service


  • As part of its Bus Modernization program, the MBTA procured 5 new electric, battery-powered articulated buses with a $10 million grant from the Federal Transit Administration.
  • MBTA needed a comprehensive audit and analysis of this next-generation bus fleet, including the Battery Electric Bus fleet as well as the Electric Trolley Bus fleet.
  • It was critical to audit and assess power demand to determine the electrical parameters of the equipment and loading of the auxiliary transformers, as well as efficient charging schemes, utility costs, and projected emissions saved.


  • Delivered comprehensive load flow studies to determine loading on the distribution system, charger feeder cable and busbar voltages
  • Evaluated effects and benefits of employing diesel heaters during extreme winter conditions
  • Reviewed years of maintenance data on fleets both at MBTA and at peer agencies to accurately project future maintenance requirements
  • Collaborates with MBTA to review documentation on an ongoing basis to develop an expert understanding of the vehicle fleet and other key considerations informing fleet and facility planning.
  • Key considerations included operating procedures, maintenance statistics, operating and maintenance cost information, key reliability performance indicators, vehicle specifications, service characteristics, utility costs and pricing strategies, inspections and corrective work performed on the buses, and peer system performance.


  • Leveraged gathered insights to develop a Life Cycle Cost (LCC) model to compare total cost of ownership (TCO) of the ETB and BEB fleet combined.
  • Determined optimal battery charger locations and supply cable routing based on in-depth depot site survey at the Southampton maintenance facility.
  • Developed a vehicle evaluation model and enabled effective evaluation capabilities for future vehicle technologies.

Project numbers

2040, the year MBTA hopes to have a fully electric bus fleet
60 to 100 miles per charge for BEBs
$4.5B invested in facilities by MBTA to support BEBs
$100 million invested annually to increase fleet of BEBs

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