District Energy marks 40 years in St. Paul with new hydrogen generator

Frederick Melo, Pioneer Press
·4 min read

When oil prices more than quadrupled during the national energy crisis of the 1970s, downtown St. Paul’s coal-powered steam plant was already creaking toward the end of its functional life.

Alarmed as much by rising energy costs as by the rising steam seeping up through cracks in the downtown sidewalk, then-Mayor George Latimer convinced city building owners to back a new downtown-specific utility that would seek innovative ways to heat structures and keep energy prices steady. The St. Paul District Energy system roared to life 40 years ago this month — September 1983 — with the downtown Central Library, now known as the George Latimer Central Library, as its first client.

“It was established to be a model for the nation,” said Ken Smith, chief executive officer of District Energy, during a plant tour on Tuesday.

The nonprofit utility — the largest hot water heating system in North America — now pumps hot water through an intricate system of underground pipes to more than 80% of downtown and the surrounding area, or 30 million square feet of structures, from the State Capitol campus to the Mount Airy Homes, United Hospital, St. Paul College and some buildings on the city’s West Side.

District Energy also cools upwards of 60% of the downtown area through a chilled water storage system, with utility rates that over the years have climbed slower than inflation.

‘Fuel-flexible’

The “fuel-flexible” plant, constructed to adopt new fuel sources as they come online, began moving away from coal and adding waste wood to its line-up in the 1980s and ’90s.

District Energy, which now derives more than half its fuel from biomass, eventually abandoned coal altogether in 2019, though it still relies heavily on natural gas. That may not be true for long.

In February, Gov. Tim Walz signed a bill mandating that utilities switch to entirely carbon-free energy sources by 2040.

On Tuesday, District Energy officials received lease approval from the Ramsey County Board of Commissioners to use part of the county’s adjoining lot on Kellogg Boulevard — the former site of the West Publishing buildings — to host a hydrogen generator, opening the door to experimentation with different fuels that could help achieve carbon-neutrality in the years ahead.

The three-year pilot program is funded by the U.S. Department of Energy and organized hand in hand with the National Renewable Energy Laboratory and Caterpillar Inc., with the goal that District Energy will continue to use the hydrogen generator after the three years after up.

For district energy systems, “it’s very uncommon in the United States,” Smith said. “It’s new, which is why the Department of Energy was so interested.”

Huge influx of wood — and more on the way

Smith, an electrical engineer by training, has served as leading planner on energy projects ranging from the Pentagon to Ronald Reagan Washington National Airport in D.C. and Ben Gurion International Airport in Israel. After 17 years with District Energy, he’s eager to see the utility expand, in terms of both customers and technology.

“We’d like to continue to grow the system, absolutely,” he said.

To heat and cool downtown, the nonprofit relies on some 250,000 tons of waste wood a year — or 1,000 tons of wood per day — mostly in the form of tree trimmings and dead or damaged trees, much of it the result of the dreaded Emerald Ash Borer and Dutch Elm disease before that.

Smith believes the Emerald Ash Borer is still a few years away from hitting its peak. With as much as one-fifth of the metro’s tree canopy consisting of ash trees, he expects a deluge of dead and damaged trees from across the area by 2027 or 2028.

In forestry circles, the trees have been dubbed “widow-makers” because their brittle tops can snap off as they decline, sending branches onto streets and sidewalks. Once more municipalities realize they have a public safety hazard on their hands, Smith predicts biomass facilities will be swimming in supply.

Flooding provides an additional source of drift wood. Around this time of year, some 40 to 50 truckloads of leftover, end-of-season mulch arrives daily. Overall, less than 1% comes in the form of palettes from construction sites.

Consulting business

Once exclusively known as a downtown St. Paul utility, District Energy has taken its talents on the road, serving as a manager or consultant on utility projects across the country.

Its subsidiary, Ever-Green Energy, manages 10 district systems, including St. Paul’s Energy Park Drive, the Milwaukee Regional Medical Center, Oberlin College in Ohio, the Illinois Institute of Technology and Duluth’s city-owned Duluth Energy Systems.

Elsewhere, the utility has served as a consultant, helping higher education institutions like Kenyon College and Denison University, both in Ohio, develop a master plan toward carbon neutrality or otherwise fine-tune their energy planning.

Smith said while St. Paul District Energy is the largest hot water heating system in North America, it will soon be surpassed by a district system in Ottawa, established with District Energy’s help.

District Energy employs 90 people, or 165 including its Ever-Green Energy subsidiary.

Related Articles