King County Executive Dow Constantine was joined by Seattle and federal representatives to break ground on Metro’s first 100% electric bus base, which 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 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.”

King County Metro’s New ZEBs Facility

The new 544,000-square-foot base will include maintenance facilities and charging infrastructure for the next-generation battery-electric buses 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.

Construction of the $115 million base will be directed by McKinstry 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. Together, these and other project features achieve Platinum status on the County’s Sustainable Infrastructure Scorecard as required by the Green Building Ordinance.

Drawing Power

Building on years of partnership with utility provider Seattle City Light, Interim Base will use six to 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 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 disproportionately borne the brunt of the 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.