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REIT Pilots Project To Use Sewer Water To Heat Buildings In 1.6M SF Development

The minds behind the nation's leading life sciences real estate developer are in the sewer — specifically the sewer system of Seattle and the potential energy contained within.

The area in Seattle's South Lake Union neighborhood where Alexandria Real Estate Equities is planning a 1.6M SF life sciences campus.

Alexandria Real Estate Equities is mining the thermal energy produced by King County’s Wastewater Treatment Division sewer system to heat its five-building, 1.6M SF Alexandria Center for Life Science — South Lake Union megacampus. 

One of the first large-scale commercial projects in the nation to use sewage heat recovery, the system is expected to provide heat to 70% of the campus once it comes online in 2025, according to a press release issued by the county. The proliferation of these projects is billed as not only able to reduce energy costs but also to combat climate change by reducing commercial property carbon emissions, one of the largest contributors to greenhouse gases. 

“Our South Lake Union Energy District demonstrates our innovative approach to decarbonizing our laboratory buildings,” Alexandria Senior Vice President Eleni Reed said in a statement. “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 South Lake Union campus, a few blocks from Amazon's headquarters, is also the first project to tap the King County program aimed at commercial developments, with two more spots up for the taking. Alexandria will pay the county costs for reviewing the project design and a half-cent-per-ton-hour fee for the heating transfer for the first three years of service. 

Sewer heat reclamation systems look to capture the ambient heat from warm water dumped by toilets, washing machines and showers into the sewer system through a heat energy transfer station along the sewer line route. That station takes warm wastewater and pumps the heat — generally around 70 degrees year-round within the King County system — into a clean water pipe system, which is then circulated to specific properties to provide heat in the winter and cooled air in the summer, NPR reported.

It’s a move that could go a long way toward reducing the energy consumption of buildings, especially since U.S. households dump enough wastewater into sewer systems to heat 30 million homes, NPR reported, citing Department of Energy data. U.S. buildings account for 70% of electricity use and about 30% of greenhouse gas emissions, according to a National Renewable Energy Laboratory 2022 report. 

The developer of the National Western Center redevelopment in Denver also installed a sewer heat transferring system to heat the 1M SF event facility, NPR reported. King County is aiming to reduce carbon emissions by 99% at South Lake Union compared to typical Seattle lab buildings, according to the press release. 

“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,” King County Executive Dow Constantine said in a statement.