'Test drive' demonstrates county's ability to generate energy from waste during power shortages

Investments in waste-to-energy resources at King County's South Plant water treatment facility in Renton are already paying off for area ratepayers.

On Monday afternoon, July 24, when a record-breaking heat wave pushed temperatures above 90 degrees, King County helped ease demand on the region's electricity grid by operating the plant on power produced by methane gas from sewage being treated there.

In just 45 minutes following a request from Puget Sound Energy (PSE), King County fired up the plant's waste-to-energy system to start operating off the grid. In four hours, the treatment plant's turbines generated 6 megawatts of electricity, more than what was needed to operate the plant. The surplus power was sold back to PSE.

"Our investments in converting waste into energy resources and our collaboration with Puget Sound Energy have not only allowed us to prepare for the type of power shortages the Northwest experienced in 2000, but have put us in position to produce energy to help others," said King County Executive Ron Sims. "This helps protect us from volatile energy rates during power shortages, and provides a reliable source of renewable energy."

"The drill proved an excellent opportunity for PSE and King County to partner to the region's benefit, said George Pohndorf, director of Major Accounts at PSE. "King County was able to keep the treatment plant running on its own power, easing strains and contributing to the overall electricity grid."

King County and PSE have worked in partnership for the past five years to increase flexibility during the sort of energy shortages that resulted in rate spikes in 2000. Last year, King County also began a resource conservation partnership with PSE that is saving the county money and enhancing the county's energy and environmental stewardship.

South Plant's waste-to-energy cogeneration system is designed to provide standby power, but it can also be used during periods of high energy demand, which can reduce peak load charges. The system can produce up to 8 megawatts of electricity, enough power to operate the plant most days of the year.

Many of South Plant's process facilities are powered by its methane gas every day and excess gas is sold, but the plant only generates electricity from the cogeneration system when market rates for electric power spike due to increases in demand.

King County also operates innovative fuel cell technology continually at the South Plant. The fuel cell power plant produces 1 megawatt of electricity, enough to power the equivalent of 800 homes.

People enjoy clean water and a healthy environment because of King County's wastewater treatment program. The county's Wastewater Treatment Division protects public health and water quality by serving 17 cities, 17 local sewer utilities and more than 1.4 million residents in King, Snohomish and Pierce counties. Formerly called Metro, the regional clean-water agency now operated by King County has been preventing water pollution for more than 40 years.