

Transit Bus Focused
Transit buses typically run cyclical, repetitive routes with predetermined schedules. Some buses cycle quickly, enabling frequent fast charges throughout the day. Others cycle more slowly, which works better with overnight charging at the bus facility. Connecticut has selected to recharge the BEBs overnight at their respective bus depot while the electric grid has excess capacity. Also, the many stops and starts of typical transit routes makes these vehicles ideal for electrification. Electric buses are at an efficiency advantage over diesel buses when stopping because they can recoup kinetic energy losses via regenerative braking. They are also at an advantage when accelerating from a stop because electric motors operate optimally over a wide range of speeds vs. diesel engines that need to operate at higher RPMs.
Electric Bus Charging Station
The energy storage systems of a BEB are large (100-800 kWh) and the batteries have to be periodically charged to operate. BEBs can be charged by plugging into a commercially available charging station typically located at the bus facility the bus returns to every night. BEBs can also be charged en route using a variety of technologies that Connecticut may explore in the future, such as overhead chargers or inductive loop charging. Each approach requires a different charging infrastructure system and impacts the BEBs lifecycle costs and benefits. There are several plug-in chargers installed across each CTtransit division as well as the Greater Bridgeport Transit Authority. However, the CTtransit Stamford facility is currently in design for the first overhead pantograph fast charger in the state. This will allow BEBs to charge in a more efficient manner.
CTDOT is currently working with the public utilities to determine the best course of action for a managed electric bus charging plan that would minimize impacts to the electrical grid and mitigate the impacts of peak demand charges on the operation of the electric transit buses.
Connecticut's Commitment
Connecticut has identified electric vehicle deployment (both in the light-duty and heavy-duty sector) as among the primary solutions for achieving its statutorily required economy-wide greenhouse gas (GHG) reduction targets of 45% and 80% below 2001 levels by 2030 and 2050.
In 2019, the Connecticut General Assembly committed to electrify 50% of Connecticut’s light-duty fleet purchases and 30% of the heavy-duty fleet purchases, including transit buses by 2030.
In July of 2020, Connecticut joined with other Northeast states to sign a Medium-Heavy Duty Zero Emission Vehicle Memorandum of Understanding to work collaboratively to advance and accelerate the market for electric medium- and heavy-duty vehicles, including school and transit buses.