Safeguarding Seattle's Wastewater Treatment with Backup Power System
West Point Power Quality Improvements
Hoffman built a 24,000-SF building at the West Point Treatment Plant, which houses backup power systems, including a 44-ton battery, to prevent potential voltage sags from the Seattle City Light transmission line. To support the heavy load, Hoffman poured a 4-foot-thick foundation made of 1,600 tons of concrete, in three early morning pours.
The new building includes support features, such as fire suppression, maintenance access, and HVAC equipment. This $113 million project is a capital improvement at the 1.45 million SF treatment plant, where King County is investing more than $800 million over 10 years.
The backup power system is critical because the treatment plant is at the end of the City Light transmission line, making it more vulnerable to voltage sags. In 2019, a power outage led to a spill of 11 million gallons of wastewater into Puget Sound, prompting the King County Council to approve the funding for the power quality improvements.
