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King County Executive News

King County Executive News
Aug. 24, 2011

Tapping sewer lines for heat and energy in Seattle’s Interbay area proposed by Executive

Pioneering waste heat technology to be tested for the first time in the region

King County would be among the first in the nation to test a new technology that captures heat from sewer pipelines and redistributes the energy to nearby buildings, under a pilot project proposed today by King County Executive Dow Constantine.

"This exciting opportunity is strongly aligned with County goals to reduce reliance on fossil fuels and recover resources from wastewater," said Executive Constantine. "In the future, it may foster the kind of environmentally friendly development that creates jobs and livable communities, and we are happy to be among the first in the nation to pilot this work."

District energy systems produce energy from a central plant that can be piped underground to nearby buildings, replacing the need for boilers, furnaces, or air conditioners.

Under the Executive's proposal sent today to the Metropolitan King County Council, the County's Wastewater Treatment Division would partner with a private Seattle-based company, FreeHold Group LLC., to build a district energy system that would extract heat energy generated inside the Elliott Bay interceptor and use it for heating and cooling in Seattle's Interbay neighborhood. The interceptor is a major pipeline that carries wastewater from downtown Seattle to the West Point Treatment Plant.

"I was pleased to advocate for this innovative clean energy idea after learning about it last year during a walking tour of Interbay with FreeHold Group LLC," said Councilmember Larry Phillips, who represents Interbay on the King County Council. "This project will be a win-win, bringing clean energy to Interbay businesses and a return on investment for county ratepayers."

The partnership agreement provides King County access to the company's data to evaluate the cost-effectiveness of the technology and the commercial viability of developing new markets for its waste energy.

King County is also entitled to royalty payments on the energy sold and to share 50 percent of any future renewable energy credits.

The agreement terms also ensures the company assumes responsibility for costs or risks associated with the project.

This release is also posted on the website for the Department of Natural Resources and Parks at