NRRI  >  Pumped Hydro Energy Storage (PHES) Using Abandoned Mine Pits on the Mesabi Iron Range of Minnesota

Last Update Wed Apr 18 15:10:00 CDT 2012

Pumped Hydro Energy Storage (PHES) Using Abandoned Mine Pits on the Mesabi Iron Range of Minnesota

Objective Progress / Results

The Mesabi Iron Range has been mined for over 100 years. In doing so, a large number of open pits and underground mines were created along its 120 mile length. This project’s main question is – what potential pumped hydro energy storage sites on the Mesabi Iron Range would support a closed-loop pumped hydro energy storage facility, and can the facility be constructed in an environmentally sound manner?The report was issued at the end of October and the project concluded. Results show that the Iron Range has a number of sites that could be potentially deployed for energy storage using the PHES concept. No dramatic fatal flaws in adopting the technology in northeast Minnesota were found as long as future mining of minerals is considered in making the final economic assessment of project viability for a given site.


PHES facilities are constructed to add stability to a local or regional energy grid, i.e., no peaks or valleys in the amount of electricity available to all consumers. These energy storage facilities are constructed using an upper reservoir, which is twice the size of the lower reservoir. Water is released from the upper reservoir through penstocks, which carry the water to the turbine(s) that produce the electricity. Generally, water is released during the day and pumped back to the upper reservoir during the night. The “head” (difference in elevation between the upper reservoir and the top of the lower reservoir) needs to be a minimum of 350 ft. These are basic criteria for locating a facility on the Mesabi Iron Range. Other criteria such as environmental impact, land ownership (surface and minerals), wetlands, archaeological sites, engineering and geotechnical considerations, etc., all impact the siting of a PHES facility.

Previous Activity / Results

This work has shown that various scenarios can be used to adopt this energy storage strategy for various locations on the Mesabi Iron Range. The Environmental team went through typical items that would be important for an Environmental Impact Statement (EIS) to be developed; they have interviewed various stakeholders about environmental concerns. The Policy team conducted extensive interviews to gauge public acceptance and potential roadblocks to concept implementation. The St. Anthony Falls Laboratory identified structural and equipment requirements for a model facility; the Geotechnical team characterized structural conditions that may exist at various locations across the Range in terms of rock integrity and quality. It was planned that a final report for this project would be issued at the end of October 2011.

Start Date 07/01/2010
End Date 12/31/2011

Principal Investigator

Steven Hauck CoPI

Elizabeth Wilson CoPI

Donald Fosnacht PI

Jeffrey Marr CoPI

Nathan Johnson CoPI

Research Collaborators

Minnesota Power & Great River Energy