Ahead of Earth Day, Mayor Muriel Bowser has announced that 14 electric buses will join the D.C. Circulator fleet, hitting the streets May 1. This will be the largest electric bus fleet in the D.C. area and one of the largest electric bus fleets in the nation, according to a press release.

These buses are known as Proterra E2 Catalyst Electric Buses, which are manufactured in the U.S. and run on 100 percent battery electric propulsion. The buses will serve all six D.C. Circulator routes, representing 18 percent of the total D.C. Circulator fleet.

With this new electric fleet, this will displace more than 88,900 gallons of diesel per year and eliminate nearly 244,000 pounds of carbon dioxide emissions annually. Cost savings are estimated at more than $6 million over the 14 Proterra buses’ 12-year lifetime.

In a statement, Bowser said, “This new fleet of electric buses will support our efforts to make Washington, D.C., the healthiest, greenest, and most livable city in the nation. The D.C. Circulator is one of the most popular transit systems in the city, and with this addition, we’re doing more to ensure we remain a sustainable, multimodal city for generations to come.”

The D.C. Circulator provides transportation to more than 25 museums, monuments, and memorials along the National Mall with more than 5 million trips per year. It only costs $1 to ride.