The city of Chicago has been working to add all-electric buses to its public transportation system as part of a 2019 commitment to convert 100% of its 1,800-vehicle bus fleet to electric by 2040. To finally add a batch of 20 all-electric buses to the fleet purchased in 2018, Aldridge Electric, Libertyville, Ill., installed three new charging stations for the Chicago Transit Authority (CTA).

The new all-electric buses can run 75-120 miles on a single charge that takes between 5 and 10 minutes to complete. It is estimated that each one of these buses will save the CTA more than $25,000 annually in net fuel costs, adding up to $300,000 over a bus’s estimated 12-year lifespan.

The charging stations were added to the CTA’s Chicago Avenue garage, Navy Pier and Chicago/Austin bus terminal.

Aldridge crews installed new 500-kilowatt (kW) AC/DC charging equipment, charging masts, DC power and signal cabling, along with a service connection to CommonWealth Edison’s (ComEd) system at each of the three sites.

At the garage, crews installed a 500kW charging system, pantograph for charging connection to the bus and a 125kW depot charging unit with a plug-in style charging connection. Chicago Austin and Navy Pier are new station sites, so the work included building infrastructure, ComEd service connection, 500kW charging systems and mast arm pantographs for the bus charging connection.

Aldridge Electric brought some innovative methods to the job sites. They prefabricated designed steel racks for underground conduit and used project planning tools to help plan work sequencing. They also leveraged subject matter experts from various divisions, such as cranes and rigging plans, setting equipment and structural bolting done by IBEW Local 134.

Working during the COVID-19 pandemic caused Aldridge to change how they communicate with designers and others who could not physically be on-site.

“A big obstacle early on was trying to navigate the integration of the system with a designer halfway around the globe in Denmark,” said Colm Maloney, general foreman at Aldridge. “We would have to schedule calls to make sure those in the field who had the questions were able to get answers relayed as quickly as possible. Due to the pandemic, the on-site presence was not as strong as we all anticipated because of travel restrictions. So, there was a lot of communication between engineers and the field on the fly. As anticipated with a new system, there were a lot of little issues to work through, but because of that early communication, the ensuing installs were seamless.”

Aldridge’s work on the sites also consisted of signal wiring, connecting termination points and equipment commissioning.

Chicago added electric buses to its fleet for the first time in 2014. According to Mass Transit magazine, the buses provide a cleaner and quieter ride for passengers and decrease emissions of pollutants while also reducing fuel costs.