Hydropower helped turn Minneapolis into a 19th century industrial giant, and the city is turning to the river again for power.
A 10-megawatt hydropower project is in the works on the Lower St. Anthony Falls and it's a new twist to an old technology that could revive the Mississippi River's role in renewable power.
The Twin Cities already have two hydropower stations on the Mississippi, one at St. Anthony Falls and another at the Ford Dam. But engineers are finding new ways to get electric power out of the river.
Massachusetts-based Brookfield Power is installing sixteen small turbines in an unused lock in lower St. Anthony falls. They're so-called "run-of-the-river" turbines that operate in the existing river current. They don't require a new dam or interfere with navigation.
"This is what the green economy is all about," said DFL state Sen. Scott Dibble of Minneapolis.
Dibble was among a group of officials who toured the project today. It's being paid for in part with a 10-year state subsidy of a cent and a half per kilowatt hour. Lawmakers at the site said the project is an important alternative to new wind power projects that aren't practical in urban areas.
"It's about finding sources of power within our existing framework and structure," he said. "This is going to be baseload power. It's going to be a steady supply of energy that can supply 6,000 or 7,000 homes in Minneapolis going forward."
Project manager Steve Mockler said construction started this spring and work will soon begin on the actual powerhouse for the hydro station. It will generate electricity with new Austrian-made turbines. They're compact enough to fit inside existing dams.
"These are sort of like a six-foot by six-foot box fan, like you would put in your window," Mockler said. "It's just big, and then the way it utilizes power, it doesn't use an existing generator, like you would see on conventional hydro, which is spinning up on the powerhouse floor."
Mockler said the new machines combine the water turbine and the electrical generator into a single piece of equipment, in the river. A similar project is being tested in Hastings.
The new Minneapolis hydro station isn't a big project. At 10 megawatts, it's only half the size of the hydro station on the Ford Dam and only about one-fiftieth of the size of the proposed Big Stone II coal fired power plant in South Dakota that was shelved earlier this week.
The Minneapolis project will generate about 40 construction jobs while it's being built. It will cost about $35 million and start making electricity late next year.