Skip to main content
King County Logo
Nov
05

King County and Alexandria Real Estate Equities, Inc. launch sewer heat recovery at new South Lake Union campus, among first in the nation to tap wastewater heat for renewable energy

Summary

King County and Alexandria Real Estate Equities, Inc. are partnering to draw heat from a large, underground sewer pipe to heat a 1.6 million-square-foot mixed-use life science mega campus in South Lake Union. This is one of the first large commercial projects in the nation to save energy using sewer heat recovery technology, demonstrating how public-private collaborations can significantly reduce greenhouse gas emissions.

Aerial photo showing the Space Needle with the new South Lake Union life sciences campus including existing and planned buildings at 701 Dexter Avenue North, 601 Dexter Avenue North, 800 Mercer Street and 400 Dexter Avenue North
Image courtesy Alexandria Real Estate Equities, Inc.

News

King County’s Wastewater Treatment Division and Alexandria Real Estate Equities, Inc. have launched King County’s first sewer heat recovery project at the Alexandria Center for Life Science – South Lake Union, a five-building, 1.6 million-square-foot mixed-use life science mega campus. This is one of the first large commercial projects in the nation to draw heat from the sewer system as a renewable energy source for buildings and is expected to provide 70 percent of the campus’s heating.

The heat recovery technology will draw heat from a county sewer pipe and send it through a heat pump system and network of pipes to heat the campus’s buildings, with the first phase installed below-ground at Alexandria’s 701 Dexter Avenue North development. The system is expected to come online in 2025. The temperature of wastewater in the sewer system averages 70 degrees, a consistent and reliable temperature for heat transfer.

“By fostering advanced technologies that provide reliable, sustainable, renewable energy sources for heating and cooling, King County is making it easier for commercial buildings to go green,” said King County Executive Dow Constantine. “Applying proven Sewer Heat Recovery technology is the latest progress we’ve made to re-engineer our region’s built environment, making the places where we live, work, and gather more energy efficient to cut greenhouse gas emissions."

The project is a significant step forward in King County’s plans to develop commercial interest in sewer heat recovery and to partner with the private sector on innovative solutions to save energy costs and reduce greenhouse gas emissions. Commercial and multi-family buildings account for 22 percent of countywide greenhouse gas emissions.

South Lake Union Energy District

Diagram of South Lake Union Energy District buildings including a district wastewater heat plant, district heat exchanger, in-building hydronic system and condenser water connections
Image courtesy Alexandria Real Estate Equities, Inc.

“As the preeminent owner, operator, and developer of collaborative life science mega campuses, Alexandria has long been a leader in sustainability,” said Eleni Reed, senior vice president and head of sustainability at Alexandria Real Estate Equities, Inc. “Our South Lake Union Energy District demonstrates our innovative approach to decarbonizing our laboratory buildings. This large-scale wastewater heat recovery system will provide an alternative energy source to heat our buildings and will improve building resiliency and operating performance.”

The system is manufactured by British Columbia-based SHARC Energy and can be used for both heating and cooling purposes. As an alternative to traditional energy sources, King County’s sewer system heat is expected to reduce carbon emissions by 99 percent compared to a typical laboratory building in Seattle.

Recognizing the untapped benefits of sewer heat recovery, the King County Council authorized the Wastewater Treatment Division to launch a pilot program, and in 2020 the Division began accepting applications for three spots in the program for commercial users. Alexandria is the first project to move forward with installation. There are two spots remaining in the pilot program.

The project reached a major milestone this summer when crews with contracting company McKinstry cut and connected the County’s original 100-year-old brick-lined main sewer line to Alexandria’s system, proving that such a system can be installed in a dense, urban landscape. Already in use in other countries such as Canada, Germany, and Japan, sewer heat recovery is an affordable, renewable energy alternative to traditional methods used to heat and cool buildings.

King County is encouraging other commercial real estate entities to apply for the two remaining open spots in the pilot. Users pay King County for costs associated with reviewing project designs as well as a use fee of one-half cent per ton-hour of energy transferred following the first three years of service.

The benefits to commercial users are reduced energy costs; contributions to green building certification; financing supports such as King County’s C-PACER Program that help developers meeting stringent energy codes; and significant reductions in potable water use. In the future, projects may be eligible to earn state renewable energy credits, making these projects even more financially attractive.

Resources

Quotes

By fostering advanced technologies that provide reliable, sustainable, renewable energy sources for heating and cooling, King County is making it easier for commercial buildings to go green. Applying proven Sewer Heat Recovery technology is the latest progress we’ve made to re-engineer our region’s built environment, making the places where we live, work, and gather more energy efficient to cut greenhouse gas emissions.

Dow Constantine King County Executive

Sewer heat recovery is a creative approach to reach our climate goals, and I am very pleased to see that it will be coming to South Lake Union. It will take innovative and cross-sector partnerships for our region to develop sustainably, create eco-friendly jobs, and save energy, and I believe this is an excellent first step.

Jeanne Kohl-Welles King County Councilmember 

As the preeminent owner, operator and developer of collaborative life science mega campuses, Alexandria has long been a leader in sustainability. Our South Lake Union Energy District demonstrates our innovative approach to decarbonizing our laboratory buildings. This large-scale wastewater heat recovery system will provide an alternative energy source to heat our buildings and will improve building resiliency and operating performance. 

Eleni Reed Senior Vice President and Head of Sustainability, Alexandria Real Estate Equities, Inc.

The partnership between King County and Alexandria portrays a framework that can be used nationwide for electrifying and decarbonizing a building’s heating and cooling loads, while reducing energy costs, saving freshwater usage in cooling towers, creating ‘green’ economy jobs, and helping achieve climate action goals and targets at the federal, state and county level.

Michael Albertson U.S President, SHARC Energy

McKinstry is proud to be a trusted design-build partner working to deliver on Alexandria’s vision for the project, including bringing to fruition the heating and cooling system that’s putting this project on the map as one of the largest sewer heat recovery systems in North America. The new campus creates more than 5,200 construction jobs for our local economy and bolsters the Puget Sound region’s green economy. 

Ash Awad President and CMO, McKinstry

Contact

Alison Hawkes, King County Wastewater Treatment Division, 206-848-0947

expand_less