King County earns national environmental award for generating electricity from methane gas

2005 Archived News

A King County project that generates electricity using methane gas from sewage treatment has earned the 2005 National Environmental Achievement Award for excellence in research and technology from the National Association of Clean Water Agencies, or NACWA.

King County's Wastewater Treatment Division received the award for its Fuel Cell Demonstration Project at the South Treatment Plant in Renton. Using gas from wastewater-solids digesters at the treatment plant, a fuel cell power plant produces up to 1 megawatt of electricity, or enough to serve 800 households.

King County uses the electricity to run some treatment plant equipment, cutting power costs about 15 percent. The molten-carbonate fuel cell, largest of its kind in the world, began operating in April 2004.

Electrical equipment in the fuel cell power plant that converts DC current to AC.

If the demonstration project is successful, King County will continue to use the fuel cell to produce energy for the treatment plant. The U.S. Environmental Protection Agency and Fuel Cell Energy Inc. of Danbury, Conn., are partners in the project.

"To reduce energy costs and air emissions, King County is searching for innovative ways to provide electricity for its wastewater treatment plants," said Wastewater Treatment Division Director Don Theiler.

"Our demonstration project moves the county into the 'green' power arena," Theiler said. "Power generated from the fuel cell will be green in at least three ways: It uses a renewable fuel, wastewater digester gas. It produces power efficiently. And it emits fewer pollutants than combustion engines."

NACWA, formerly the Association of Metropolitan Sewerage Agencies, gives annual environmental achievement awards to people and member agencies that make outstanding contributions to environmental protection and wastewater management. NACWA presented the award May 2 at its national conference in Washington, D.C.

The research and technology award is given to agencies that develop technological innovations in wastewater treatment or biosolids use and disposal. The research project or technological innovation must have practical application and relate directly to the collection, treatment, reuse or disposal of wastewater or biosolids.

Fuels cell are electrochemical devices that convert chemical energy from fuels containing hydrogen directly to electricity and heat. Combustion is not needed.

Similar to a battery, the fuel cell at the King County plant has hundreds of individual cells. Cells are grouped to form a stack. Each fuel cell contains an anode, cathode and electrolyte. Methane gas, a hydrogen-rich fuel, enters each stack and reacts with oxygen to produce electricity.

More information about the project is available on the county Web site.

King County's Wastewater Treatment Division protects public health and water quality by serving 17 cities, 17 local sewer agencies and more than 1.4 million residents in King, Snohomish and Pierce counties. Formerly called Metro, the regional public utility has been preventing water pollution for 40 years.