King County Metro breaks ground in Tukwila on electric bus charging hub

The Interim Base will charge dozens of buses serving South King County.

King County Executive Dow Constantine and representatives from the City of Tukwila, the Federal Transit Administration, and Seattle City Light broke ground on King County Metro’s first 100 percent electric bus base that will support 120 next-generation buses scheduled to arrive in the next two years.

“The future of transit is electric, and today we’re building Metro’s infrastructure to deliver the bus network of tomorrow,” said Executive Constantine. “A new 100% electric base for 120 new zero-emission buses will help us combat carbon emissions, push back against our changing climate, and support this new fleet for decades to come.”

The new 544,000-square-foot base will include maintenance facilities and charging infrastructure for the next-generation battery-electric buses that are scheduled to begin service in 2026. It will be located south of the Tukwila test charging facility that is used to charge the 40 long-range battery-electric buses that have been in service since 2022.

“Metro is leading a sustainability transformation and today’s event celebrates a vital milestone,” said Metro General Manager Michelle Allison. “As we transition to a zero-emission fleet, the new Interim Base in Tukwila will be the blueprint to construct future bases and will be a hub of innovation. New zero-emission vehicles and our world-class technicians and other transit professionals will soon be here.”

Construction of the $115 million base will be directed by McKinstry Construction and will feature several sustainability efforts to reduce energy consumption and reuse materials. The project will use drought-resistant native species to minimize the need for irrigation and reduce the heat island effect by replacing dark asphalt with lighter-colored concrete.

Building on years of partnership with Seattle City Light, Interim Base will use 6-10 megawatts of electric energy to charge Metro’s and King County’s zero-emission bus fleet. Interim Base will also be home to zero-emission non-revenue vehicles, including EV sedans and an electric yard cart, all powered by new charging infrastructure being installed at the adjacent parking garage. Additionally, Metro says it is investing in software technology to support charge management and efficient operations at the site.

The buses that will operate out of this base will be focused on serving the communities of South King County that have been disproportionately impacted by pollution generated by fossil fuels.

As Metro prepares for a zero-emission future, Interim Base is intended as a prototype for future battery‐electric bus deployment and base electrification throughout the county. As an innovation hub, continuous improvement and lessons learned at Interim Base will inform the future work of Metro and other transit agencies around the world.