How the MBTA’s Plan to Use Electric Buses Could Benefit the Power Grid

The MBTA appears to be advancing its plan to move forward with electric buses with its goal of electrifying the fleet by 2040. In addition to improving the environment by reducing emissions, employing cleaner, fully electric buses may also benefit the power grid.

Writing for the Commonwealth Beacon, Seth Kaplan, who previously served at the Conservation Law Foundation, said making the switch to electric buses would turn bus garages into energy hubs that “employ smart technology that allow batteries on parked buses to export power out to the grid when the energy system that powers our society needs a little help.” 

“If the MBTA were to take a leadership role, harnessing the full potential of the electric bus depot as a smart energy hub, the benefits in terms of dollars saved, improvement to the regional energy system, and pollution avoided would be substantial,” Kaplan said.

According to Kaplan's research, an electric bus the length and size of those in the T's typical workaday fleet has a battery that holds more than 350 kilowatt-hours (kW-hrs) of power. 

Larger buses, like the “articulated” buses in use on routes such as the Silver Line and the 39 bus through Mission Hill and Jamaica Plain, contain a battery that holds more than 500 kW-hrs. An average Massachusetts household uses approximately 20 kW-hrs of electricity per day. Residential battery installations offering backup power during a blackout are usually between 10 kW-hr and 15 kW-hr capacity. 

Kaplan further argues that energy hubs like bus garages or depots will become more and more integral in the work toward creating a more sustainable power grid. 

“Our grid will, increasingly, be home to variable 'loads' that consume power — like the electric heat pumps that can heat our homes during the winter and cool them in the summer,” he said.