County’s New System Helps Prevent Untreated Wastewater Spills Into Puget Sound

Operators at King County’s West Point Treatment Plant say a powerful new onsite battery system is keeping Puget Sound clean by preventing potential spills of untreated wastewater during power disruptions.

Installed in June 2024, the 16.8-megawatt battery system powered critical pumps during 78 power interruptions over the past year. Engineers estimate that 15 of those events were severe enough to have potentially triggered emergency bypasses of untreated wastewater if not for the battery backup.

King County Executive Shannon Braddock praised employees for building and operating what she described as a first-of-its-kind battery system.

“What began as an award-winning engineering marvel is now an operational success,” Braddock said. “The onsite battery system we installed at West Point Treatment Plant is delivering exactly what we promised: providing reliable power that protects Puget Sound, even when our region experiences catastrophic weather events.”

The system’s importance resonates beyond the plant itself. Leonard Forsman, Chairman of the Suquamish Tribe, said reliable wastewater treatment safeguards tribal and community health.

“Protecting our ancestral waters from untreated wastewater is fundamental to a healthy and thriving ecosystem,” Forsman said. “It’s a relief to learn that the improvements made at the West Point Treatment Plant are working, and we appreciate King County’s investment in the infrastructure needed to prevent future spills.”

Operators say the Power Quality Facility, which houses the battery system, proved especially reliable during the wet weather season when the plant is most vulnerable to power disruptions. The batteries maintained consistent power each time voltage from the electrical grid dipped below critical thresholds.

Clinton Fisher, acting Instrumentation and Electrical Supervisor, said he was initially skeptical.

“I had my doubts at first, but after seeing how it’s worked — and what it’s helped us avoid — I’m a believer,” Fisher said.

Extreme weather events have caused a dramatic increase in power disruptions at the state’s largest treatment plant compared to five years ago. During the powerful “bomb cyclone” windstorm in November 2024, the facility experienced 28 voltage sags, requiring battery backup seven times to keep pumps running. Another windstorm in February caused 11 voltage sags and two full outages, with the battery system stepping in four times.

Sean Kehoe, Operations Supervisor at West Point, said the battery system has transformed how operators respond during storms.

“Power outages used to be completely out of our control,” Kehoe said. “When it’s windy and the lights flicker, we still brace ourselves, but now we can breathe easier knowing that the Power Quality Facility will help keep our pumps running.”

King County completed the ambitious capital project just three and a half years after former Executive Dow Constantine declared an emergency to accelerate construction. Within two years, crews built the 24,000-square-foot facility, which houses more than 2,000 batteries and 140 solar panels that provide clean power for lighting, heating, ventilation, and cooling systems.

King County Councilmember Claudia Balducci said the project exemplifies successful local infrastructure investment.

“This is one of the most successful local infrastructure projects I’ve seen in a long time and shows what government can do when we act with urgency and creativity,” Balducci said. “Protecting our water — for the health of our people, wildlife, and future — is one of our most important responsibilities, and I am thrilled that we have this new capacity to fulfill that responsibility.”

Councilmember Jorge L. Barón said the battery system benefits the entire Puget Sound region.

“A storm system may be out of our control, but being ready to respond to a storm isn’t,” Barón said. “In its first year, the Power Quality Improvement Project at West Point has responded to unexpected power interruptions and proven its ability to keep power supplies consistent and our waters clean.”

Kamuron Gurol, Director of the King County Wastewater Treatment Division, said the battery project demonstrates the value of investing in wastewater infrastructure.

“The Power Quality Facility exemplifies the positive impact we can make to clean water by investing in our regional wastewater infrastructure,” Gurol said. “This project is one of dozens underway across our service area that are modernizing our wastewater system to be resilient to climate impacts and meet our communities’ needs for decades to come.”

John Taylor, Director of the Department of Natural Resources and Parks, said the project adds to a series of upgrades that have made West Point safer, more reliable, and more resilient to climate impacts.

“Our workforce has consistently demonstrated the ingenuity needed to modernize critical infrastructure,” Taylor said.

The Power Quality Improvement Project has earned multiple industry awards, including from the American Council of Engineering Companies. It is part of broader capital improvements at West Point, which has recently completed seismic upgrades and is in the process of replacing raw sewage pumps that have operated nearly nonstop since the 1960s.