King County Metro Transit has broken ground on Interim Base at South Campus. The facility is the agency’s first 100 percent electric bus base that will support 120 next-generation buses scheduled to arrive in the next two years. The base was originally planned as a temporary facility, but King County Metro has a long-term plan and will rename it later.
“The future of transit is electric and today we’re building King County Metro’s infrastructure to deliver the bus network of tomorrow,” said King County Executive Dow Constantine. “A new 100 percent 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 is leading a sustainability transformation and today’s event celebrates a vital milestone,” said King County 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. The Interim Base will keep them charged up.”
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-foot 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.
“King County is setting an example for major transit authorities that want to eliminate carbon emissions while increasing operational resiliency. McKinstry has worked alongside King County Metro to test and optimize charging infrastructure to ensure their zero-carbon commitment is achievable without compromising the invaluable service they provide to our communities. We are excited to break ground on the new base, as it moves not only King County a step closer to decarbonization, but all transit authorities nationwide,” said Ash Awad, president and CMO, McKinstry.
Building on years of partnership with Seattle City Light, the Interim Base will use six to 10 megawatts of electric energy to charge King County Metro’s and King County’s zero-emission bus fleet. The interim basse will also be home to zero-emission non-revenue vehicles, including Electric Vehicle sedans and an electric yard cart, all powered by new charging infrastructure being installed at the adjacent parking garage. Additionally, King County Metro is investing in software technology to support charge management and efficient operations at the site.
The agency says the buses that will operate out of this base will be focused on serving the communities of south King County. Interim Base is intended as a prototype for future battery‐electric bus deployment and base electrification throughout the county.
