Mining pits' new life as pumped-storage hydrowhat?!

Ten abandoned mining pits in Minnesota's Iron Range could have new life as pumped-storage hydroelectricity plants, according to a University of Minnesota,* Great River Energy, and Minnesota Power study.

[Hey, now: did you click on the hyperlink above? I don't put hyperlinks in posts for my own amusement, you know. They're for your viewing pleasure and learning enjoyment! Seriously though, click on them for great explanations, photos, diagrams, graphs, and more. You won't be disappointed.]

Match made in Minnesota: Wind and water "play nice" in pumped-storage hydroelectric technology.
Match made in Minnesota: Wind and water "play nice" in pumped-storage hydroelectric technology.Courtesy Steve Fareham

Pumped-storage hydroelectric technology sounds like something from a science fiction movie, but it's really just a neat combination of water and wind energy technology. What makes pumped-storage hydroelectric projects sexy is that they make it possible to store excess energy generated by wind turbines on windy days. This stored energy can then be used during the inevitable calm days -- addressing one of the biggest issues for today's wind energy industry!

How does it work?

It's basic physics, my friends: building potential energy and releasing kinetic energy. Specifically, excess energy generated by wind turbines "is used to pump water from a low-lying reservoir to a higher elevation pool" within the mine pit. This builds the potential energy of the water. Then, when that energy is demanded, "water from the upper pool is released generating hydroelectricity and refilling the lower pool." This releases kinetic energy, which can be turned into electricity.

How effective is it?

Researchers estimated that a pumped-storage hydroelectric facility built in Virginia, MN could output the same electricity as a "modest-sized" generator burning natural gas. However, at a cost of $120 million, the pumped-hydro facility would be more expensive than a comparable natural gas generator.

There are 40 U.S. locations currently employing pumped-storage hydroelectricity technology, but there are no definite plans for any such projects in Minnesota -- yet.

Read the Star Tribune's coverage of this story here.

*Including scientists from UMD's Natural Resources Research Institute, St. Anthony Falls Laboratory, and Humphrey School of Public Affairs; and funded largely by the Initiative for Renewable Energy and the Environment.

Your Comments, Thoughts, Questions, Ideas

Anonymous's picture
Anonymous says:

Hmm. I read a figure of $120 million for a 160 MW project. That's $750/kW, which is about the price of a new gas-fired combustion turbine. But the combustion turbine only has a life of 30 years, while the pumped storage plant has a life of 75 years. The pumped storage plant can also ramp up and down much faster than the combustion turbine.

posted on Fri, 12/16/2011 - 10:15pm
KelsiDayle's picture
KelsiDayle says:

Great addition to this post! Do you remember where you got your information? I'm interesting in looking deeper. Thanks, Anonymous.

posted on Tue, 01/03/2012 - 2:51pm
KelsiDayle's picture
KelsiDayle says:

Here's the Duluth News Tribune's take on the same story.

posted on Tue, 01/03/2012 - 11:17am
CameronRobertson's picture
CameronRobertson says:

I think this pumped-storage concept is very beneficial, especially during the non-windy season. Usually, wind turbines can only generate energy when there is wind. However, this pumped-storage can store excess kinetic energy for later usage. That is one smart concept indeed! It also reduces wastage of kinetic energy when the wind is at its highest peak. The unused energy can be stored to be used later. A very useful concept that reduces wastage and increases productivity.

posted on Wed, 06/19/2013 - 2:08am
michaelmaloney's picture
michaelmaloney says:

It is already one good idea to begin with by converting the abandoned mining pits into pumped-storage hydroelectricity plants. There is already some savings done there and to continue on with further savings in term of the implementation of the wind storage is a continued progression. Since that area has always been facing issues with non-windy days, then this might just be the perfect solution to address that problem. It reduces energy wastage and only utilize it when energy levels are high.

posted on Wed, 08/27/2014 - 9:50pm

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