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If Mississippi dams are removed, what happens to the hydroelectric plants? Corps plan has ripple effects

An Aug. 23, 2018, aerial photo of the Mississippi River looking downstream shows St. Paul, left, and Minneapolis. In the foreground is the Ford Bridge, which links Ford Parkway in St. Paul and 46th St. in Minneapolis. Just downstream of the bridge is Lock and Dam No. 1, with an 18 megawatt hydroelectric generator operated by Brookfield Renewable. John Autey / St. Paul Pioneer Press1 / 4
Four Westinghouse 3 Phase generators still operate in the large generator room of the hydroelectric plant on the Mississippi River, formerly owned and operated by the Ford Motor Co., now owned by Brookfield Renewable. Scott Takushi / St. Paul Pioneer Press2 / 4
The Ford Street Bridge is seen through the windows of the hydroelectric plant just downstream on the Mississippi River on Thursday, Sept. 27. The plant was built in 1924. Scott Takushi / St. Paul Pioneer Press3 / 4
Water pours over the Ford dam on the Mississippi River in St. Paul on Tuesday, July 3. John Autey / St. Paul ioneer Press4 / 4

ST. PAUL — Andy Davis can think of 42 reasons not to take out the dams of the upper Mississippi River.

That is the number of megawatts generated by hydroelectric generators between Minneapolis and St. Paul. If the dams were removed to restore the Mississippi to its original free-flowing state, that source of electricity would be jeopardized.

"When I first heard about this idea, I was shocked," said Davis, spokesman for Brookfield Renewable, a Toronto-based renewable energy company that operates two of the plants. The third is owned by Xcel Energy.

The U.S. Army Corps of Engineers has proposed selling the dams because they are no longer needed for river navigation. If that happens, the new owner could remove them — and let the waters of America's biggest river flow freely through a 6-mile canyon.

If the dams were removed, the hydroelectric facilities would close because they depend on dams to keep the flow of water steady in wet or dry weather. The three plants produce 42 megawatts of electricity an hour, which is about 368,000 megawatt hours a year. That's enough for about 30,000 homes.

The Corps is considering the sale of:

  • The Upper St. Anthony Lock and Dam, near the Third Street bridge in downtown Minneapolis. Xcel's hydroelectric plant at that site generates 14 megawatts.
  • The Lower St. Anthony Lock and Dam, a quarter-mile downstream. Brookfield owns that plant, which generates 10 megawatts.
  • Lock and Dam No. 1, also called the Ford Dam, near the old Ford Motor Co. property in St. Paul. Brookfield owns an 18-megawatt plant there.

The Corps held public meetings regarding the sale of the dams last spring and in 2019 will make recommendations about the potential sale.

Advocates for removing the dams say the river could become a recreational magnet, drawing boaters, kayakers and inner-tubers. The faster flow also would benefit aquatic life, they say.

Officials of the Mississippi National River and Recreation Area have not taken any position on the plans.

But Superintendent John Anfinson points out that the three hydroelectric plants satisfy a small part of the state's electricity needs. Hydroelectric sources account for 2 percent of Minnesota's electricity consumption, according to a June 2018 report by the U.S. Energy Information Administration.

A single plant powered by natural gas — along the Mississippi at the High Bridge in St. Paul — produces almost 13 times the power of the three hydro plants combined.

Wind turbines also could replace the megawatts generated by the three plants.

"We want these questions answered in a serious way," said Anfinson. "Can we replace this power with wind turbines? What is the trade-off?"

Metro location has advantages

But Brookfield's Davis said that the dams' locations are valuable. The hydroelectric plants are exactly where they are needed most, in the heart of the metro area.

It's more efficient to have power generated nearby, said Davis, because of "line loss" from transporting power over distances.

Few, if any, major American cities have such sources in their downtown areas. Indeed, Minneapolis was built on that location because of river power — mechanical force that first powered flour mills.

Another advantage, Davis said, is reliability. Wind and solar generation rise and fall with the weather and time of day, but river power is as steady as the Mississippi itself.

Any replacement facility, he said, also would not be as environmentally beneficial.

"Maybe it wouldn't be a green facility. Maybe it would be gas-burning," said Davis.

And "going green" is one of the state's goals.

Xcel is working to switch its power generation from fossil-fuel plants to renewable power. It is on track to hit a target of 85 percent carbon-free power by 2030, said Xcel spokesman Matt Lindstrom.

Eliminating hydroelectric power would be a step backward. "How do you lose green power in a state that wants green standards?" said Brookfield's Davis.

No purchase price has been estimated for the dams.

Davis said the companies bought the plants with the expectation of keeping them for a long time. The federal license for the Lower St. Anthony plant, for example, expires in 2056.

The proposal to sell the dams, he said, is in uncharted waters.

"There is no precedent for this. This has never been done, with a private owner of a hydroelectric site," said Davis.

"It's just a whole lot more complex than people thought."