Hydro power

Is hydro power part of the plan for Minnesota?

water turbine diagramFalling water pushes against the turbine’s blades and makes the turbine spin. The turbine converts the kinetic energy of falling water into mechanical energy. An electrical generator connected to the turbine spins as the turbine does, converting the mechanical energy into electric energy.
Image courtesy U.S. Department of Energy

Governor Pawlenty set an aggressive energy-saving goal for Minnesota to reduce use of fossil-fuel energy 15% by 2015. Pawlenty believes the goal is achievable through increases in energy efficiency and use of renewable resources. “We have among the nation’s best conservation and energy efficiency programs. We can build on this success and save significantly more energy in the coming years,” Pawlenty said. “Energy conservation saves Minnesotans real money on their energy costs, while reducing the environmental impacts of our energy use.”

One source of renewable energy that is likely not on the list for significant development is hydropower—power derived from moving water. Development of new hydropower facilities can drastically impact the local environment and often competes with other uses for the land. So although there are undeveloped hydropower resources in Minnesota, and proposals in place to develop more facilities to harness this power—including one at St. Anthony Falls—we aren’t likely to take advantage of them anytime soon because of their environmental impact.

water turbine diagramSt. Anthony Falls, Minneapolis, Minnesota

Image courtesy Xcel Energy

Evolution of a resource in the Mill City

There are several hydropower plants in Minnesota, including Xcel Energy’s hydropower plant on the Mississippi River at St. Anthony Falls.

St. Anthony Falls has a long history of providing power to the state of Minnesota. As early as the 1820s, the Falls provided power for lumberyards, turning water wheels which in turn drove saws. Later, the sawmills gave way to flour mills where the energy from the Falls turned the grindstones that helped make Minneapolis the world’s leading flour miller.

In 1882, the Brush Electric Company, which ultimately became Northern States Power Company, the predecessor to Xcel Energy, produced the first electrical power ever generated through hydro generators in North America. Flour milling along the river has declined greatly since 1882, but St. Anthony Falls continues to generate hydropower 125 years later.

fish ladderA fish ladder on the John Day dam

Image courtesy of the U.S. Army Corps of Engineers

A fishy problem

Most hydropower projects use a dam and reservoir to retain water from a river, which impacts the river ecosystems and interferes with fish migration.

So dam builders include fish ladders on or around the dams to let fish get around them. Most fish ladders work by allowing fish to swim or leap up a series of low steps from one side of a dam to another. The tricky part of the design is that the water has to fall over the steps fast enough to attract the fish to the ladder, but the water flow can’t be so fast that it prevents the fish from reaching the other side.