South Annex Base Commissioning


King County Metro


Tukwila, WA






Civic & Public

Project Team
Nick Baker
Principal—Mechanical and Commissioning
Shaun May
Project Manager
A LEED Platinum Facility for King County's Clean Energy Fleet

King County Metro is expanding its bus bases to support safe and reliable service and reduce transportation-related greenhouse gas emissions. Metro aims to lead the nation by having a fully electric bus fleet by 2040, and its new South Annex Base is a significant step forward toward this goal.

The South Annex Base will serve a fleet of approximately 250 zero emissions battery electric buses (BEB) including maintenance and operations facilities and stations for washing, vacuuming, and demountable hybrid bus fueling. The initial fleet will be diesel hybrid buses with conversion to BEB operations in the future. The completed facility will leverage best practices and technologies to support efficient, environmentally responsible operations, incorporate and provide for emerging technologies beyond those presently employed by the County, and showcase King County’s commitment to sustainability. The project is pursuing LEED v4 Platinum certification.

We are providing independent commissioning and related services for the project during predesign, design, preconstruction, construction, acceptance, closeout, post-occupancy, and warranty period phases. During the predesign to 30 percent phase, we have been heavily involved in design charrettes to define stakeholder wants and needs, as well as help define and mitigate project risks.