Award allows Duluth to explore wastewater as possible heat source

The pending reconstruction of West Superior Street offers a unique opportunity for the city to consider installing an innovative new heating system that would be the first in the U.S.

An aerial view of eight white tanks among industrial buildings next to a river
The Western Lake Superior Sanitary District treatment plant in Duluth on May 18, 2021.
Steve Kuchera / File / Duluth News Tribune

DULUTH — The U.S. Department of Energy is investing $700,000 to help local officials examine the feasibility of a heating system that could be the first of its kind on U.S. soil. Its prospective energy source? Human waste.

Ken Smith, CEO of Ever-Green Energy, said he sees great potential to harness waste heat from the Western Lake Superior Sanitary District's operations and use it to distribute heat throughout neighboring Lincoln Park while also serving Duluth's downtown and Canal Park districts. He noted that effluent at the treatment plant is maintained at a steady temperature of about 95 degrees year-round.

"In sort of a short layman's summary, this technology would use pumps to essentially move heat around, instead of burning fossil fuels to gain heat," said Mindy Granley, the city's sustainability officer.

She said Duluth is one of only 11 communities in the nation to receive funding through the federal energy program. Granley said the city also will be eligible to receive follow-on federal support to cover up to 90% of the cost of building out the infrastructure needed to bring a project forward should it be deemed worthy of further investment.

Detailed cost estimates have yet to be calculated, but are likely to run in the tens of millions, according to Smith.


It has the potential to be a model for the nation.
Ken Smith, CEO of Ever-Green Energy

"This is a really unique opportunity to bring reliable, sustainable carbon-free energy at rates that are stable and affordable to this community by using wasted energy that is already in this community," he said.

Smith called the project "a bold, big idea that is capable of delivering on those expectations," and said, "It has the potential to be a model for the nation."

"There is only a handful of these types of projects on the planet, and I've been to some of them," Smith said, referencing personal visits to view similar systems in Finland and Sweden.

The local feasibility study should be completed within a year, and timing is of the essence, because local officials hope to have the installation of the necessary new infrastructure to support a new district energy coincide with the pending reconstruction of West Superior Street . Tackling the project while the street is torn up should cut overall costs by about 40%, according to Smith.

He described the Superior Street project as "the catalyst that makes this possible."

"With the proximity to the WLSSD plant, everything is aligned to really make this transformative project possible," Smith said.

At a Tuesday afternoon news conference in Lincoln Park, Mayor Emily Larson referred to the initiative as "tremendously hopeful, exciting and visionary for this community."

“As a nation, especially of the time, it was an impressive accomplishment,” Marianne Bohren, executive director of the Western Lake Superior Sanitary District, said during a public tour Tuesday.

Larson said Duluth has been working to reduce its carbon footprint and has cut its greenhouse gas emissions from city operations by 32% since 2016.


"We hope that the project will offer a way to both decarbonize hundreds of buildings through district energy investment and also stabilize heating fuel prices into the future," she said.

"We are beyond excited about this planning grant," said Jodi Slick, founder and CEO of Ecolibrium3, a Lincoln Park-based nonprofit.

"One of the secret sauces that we have here in Lincoln Park is to take the bones of this neighborhood and figure out how we can use those bones to create a neighborhood and a community that thrives. And one of those things that is in this neighborhood is WLSSD, who has led a lot of the environmental recovery in this region," Slick said, referring to the strong partner the city has found in its local waste handler.

Peter Passi covers city government for the Duluth News Tribune. He joined the paper in April 2000, initially as a business reporter but has worked a number of beats through the years.
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