As Coal Fades, Mines Get New Life in Energy Storage

May 6, 2022

I interviewed Dr. Peter Schubert, a Professor of electrical and computer engineering and the Director of the Richard G. Lugar Center for Renewable Energy (LCRE) at Indiana University-Purdue University Indianapolis (IUPUI)

Dr. Schubert is working to enable greater clean energy penetration in Indiana and across the midwest. Among the topics I was excited to discuss was the potential for rehabilitating abandoned underground coal mines for energy storage using well-understood, off-the-shelf pumped storage technology.


Boston, Massachusetts-based Rye Development, which has a current in-design or operational portfolio of 25 projects in 10 states, on Jan. 4 announced it was developing the 200-MW Lewis Ridge Closed Loop Pumped Hydropower Storage project in Bell County. The company has filed for a permit for the project with the Federal Energy Regulatory Commission (FERC).

Michael Rooney, vice president of Project Management for Rye Development, told POWER on Jan. 5 that Rye expects the FERC application process will take a few years, while providing at least three-to-five-year construction process that would bring Lewis Ridge online by 2030.

“This is the first project we are pursuing on a former coal site,” said Rooney, who said it could be a model for future sites that could reclaim abandoned coal mines. “Rye recognizes the opportunity that certain brownfield sites offer for closed-loop pumped storage projects. Oftentimes these sites have characteristics that are beneficial for large power generation or storage applications such as existing transmission access, favorable zoning, etc.”

The project site has what Rye said is “beneficial topography,” along with proximity to transmission infrastructure.

The U.S. Dept. of Energy (DOE) has said pumped storage facilities are the most common form of energy storage in the U.S., representing 95% of all utility-scale storage. Most U.S. pumped storage facilities were built between 1960 and 1990, according to the U.S. Energy Information Administration (EIA). The agency has said about 21 GW of pumped storage is in use today. The group said that while FERC has approved a handful of new pumped storage projects since 2014, the U.S has not added any new pumped storage capacity since 2012—with just two new plants coming online since 2000.

Lewis Ridge, like other closed-loop pumped storage facilities, will feature a system that moves water between a manmade lower reservoir and a manmade upper reservoir. Water is released from the upper reservoir, and used to turn hydroelectric turbines to generate electricity. The water is than collected in the lower reservoir, and returned to the upper reservoir to repeat the process, in effect recycling the same water over and over to produce power.

Rye officials said pumped storage “offers a flexible solution to the changing grid, including the ability to store intermittent solar and wind resources moving forward.”

“Rye is the leading developer of this type of long-duration storage in the U.S.,” said Rooney, noting the company’s expertise in the hydropower sector. “As an example, Rye’s Swan Lake project is a late-stage project that will be the first closed-loop pumped storage facility built in the country when it comes online in 2026.” The 400-MW Swan Lake installation, sited in southern Oregon, also is designed to support renewable energy power generation.  

Below, similar above-ground storage project in Australia will take advantage of an abandoned gold mine.

5 Responses to “As Coal Fades, Mines Get New Life in Energy Storage”

  1. I can’t imagine that there is enough empty mine volume to make this all that significant but the concept looks useful. Really deep mines would offer a multiplying factor. Of course, digging up open volume would be even dumber than Energy Vault:

    • greenman3610 Says:

      There are thousands. Many, if not most, are connected with transmission lines to the grid. They are, of course, already permitted and have road access, allowing work to be done with minimal impacts. Many, while unimproved, are environmental hazards, leaking contaminated water etc. They represent communities where jobs have been lost and tax revenues are moribund.
      It’s a win win win.

      • John Oneill Says:

        Underground mines are often closed because they’re so much more expensive to keep open and run than open cast. Open cast often require the removal of far more overburden rock, but that’s still cheaper than shoring up and pumping dry the galleries of an underground mine. Reinforcing an old, abandoned mine, to not only avoid contamination, but also resist the daily two-way erosion of thousands of tons of fast-moving water, would probably cost even more.
        I’m very hopeful that a pumped hydro proposal currently being investigated by the New Zealand government will allow us to quit burning coal for power, especially in dry hydro years, and integrate more wind into the grid. That would complement existing hydro schemes, by pumping water nearly two thousand feet up from the South Island’s largest river, mainly in Spring, when snowmelt fills all the rivers, and power demand is low. It would store 5,500 gigawatt hours, twenty-two times as much as all current United States pumped hydro plants combined.

    • rhymeswithgoalie Says:

      Thunderf00t is great at slicing through marketing hype used to lure investors.

      Just as in previous tech transitions, there will be a lot of investment money lost in implausible, barely-plausible and just-bad-luck technology companies. Some technology companies will be monstrously huge winners. The most reliable returns when there’s a gold rush are from companies that sell the analogs of picks and shovels.

  2. rhymeswithgoalie Says:

    Finally, a video from the Australian Government!

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