Port of Seattle Alternative Utility Facility

The Alternative Utility Facility (AUF) marks an early step in SeaTac international airport’s quest for enhanced infrastructure. Its main objective is to enhance the airport’s ability to withstand utility failures by assuming control of the crucial 115kv feed, which, if not managed, could lead to significant disruptions in airport operations. Designed to emulate the operational efficiency of a data center, Mortenson drew on their expertise to create a facility that is not only forward-looking but can also evolve seamlessly with the airport’s future growth.

Navigating through an operational airport inherently comes with challenges. Close collaboration with airport authorities, coupled with a thorough understanding of airside and landside dynamics, led to the strategic placement of the project adjacent to the South Main Substation. This positioning ensures minimal interference with ongoing operations while facilitating swift emergency access.

Nestled in close proximity to a neighboring jet fuel farm, the AUF houses dual-fuel generators capable of operating on both traditional diesel and jet fuel. Outfitted with 24/7 occupancy amenities, including a full bathroom, the system ensures continuous or near-continuous uptime, delivering a reliable 30 megawatts of power through ten 3 MW generators. The comprehensive project encompasses the installation of 10 generators, a control building, Medium Voltage (MV) switchgear building, and MV automatic transfer switching building, situated on a secure campus linked to Sea-Tac Airport’s main substation by MV underground ducts. An automatic transfer switch facilitates a dependable transition between primary and alternate power sources.

In light of Sea-Tac’s perpetual operations, the paramount focus is on avoiding disruptions. Mortenson successfully executed a closed transition test to validate the efficacy of switching to alternative power in the event of an incident. Sea-Tac conducts annual testing, intentionally disconnecting utilities, prompting the generators to seamlessly take over operations for approximately an hour before reverting to primary power. Thanks to the project’s success, these transitions occur inconspicuously, without causing disruptions for passengers and personnel.