By Amanda Durish Cook

Old and new will interconnect in an innovative way if researchers at Michigan Technological University can pull off an energy storage concept that pairs some of the state’s abandoned and flooded mines with hydroelectric pumped storage.

Researchers and students at the university are studying the possibility of using an abandoned mine in the Upper Peninsula for underground pumped hydroelectric storage. Representatives from Michigan Tech and the city of Negaunee say floodwaters from the lower levels of the mines could be pumped to higher, dry levels, using old excavations as holding tanks. Such a system would be essentially invisible, leaving the surface undisturbed, they say.

Roman Sidortsov, assistant professor of energy policy, said the pilot landscaping study is focusing on Negaunee’s Mather B, an iron mine that ramped up production after World War II and shuttered at the end of the 1970s.

The two-year pilot, funded by a $50,000 grant from the Alfred P. Sloan Foundation, will likely produce a report this fall on whether an underground pumped hydro storage facility is technologically and environmentally feasible. Sidortsov said the report will be intended for a broad audience, including “developers that contemplate energy storage projects and policymakers who might support them.”

The research team will hold an April 26 brown bag lunch meeting where students who have been working on various aspects of the study will present their preliminary results, followed by a May 7 community meeting in Negaunee to provide updates on the pilot.

Researchers are at a preliminary stage in the project after holding the first meetings in December. Sidortsov said he and others are now waiting for a few feet of snow to thaw to begin accessing the mine, with student researchers planning on bringing snowshoes this week to assess the area.

“We live in a snow globe up here,” Sidortsov said in a telephone interview with RTO Insider. “We were helped in identifying the mine with city planners.”

For now, the work is focused on a “preliminary analysis to identify next steps,” Sidortsov explained. However, he said early engineering analyses relying on mine dimensions supplied by city planners are “incredibly optimistic.”

“We cannot wait to confirm those numbers,” he said.

According to Sidortsov, the “very, very back of the envelope numbers” show Mather B might be able to support up to a 50-MW nameplate capacity facility that can provide continuous output for up to three hours at a time. The facility would use surplus energy for pumping.

The idea is for a singular storage facility, but Sidortsov said research could show it’s more efficient to install multiple facilities in separate mineshafts.

Timothy Scarlett, Michigan Tech associate professor of archaeology and anthropology, said he and Sidortsov will have a better understanding of the feasibility of the project in July and August.

Until then, “we’ve been trying to under-promise and overdeliver,” Scarlett said.

Meanwhile, Michigan Tech students have already started research on surface water runoff and cybersecurity issues that could affect such a storage facility.

‘Post-industrial Landscape’

The researchers say this initial study is being conducted backward when compared to how a utility might approach a new generation project, where the design and engineering work typically come before community meetings.

Scarlett and Sidortsov said they began their work by engaging community leaders. It’s how they learned the team should choose the Mather B site instead of the original choice, the nearby Jackson mine, where a deadly accident had left miners entombed. Scarlett said the early meetings helped to uncover local sensitivities about different mines in the area. On advice from city officials, the Jackson mine was left alone out of respect for the families of the dead.

“Community members feel differently about different historic mines,” Scarlett said, adding that social acceptance of such a project is important in “post-mining, post-industrial” communities.

“It’s a sensitive issue for the community. In doing some of the research, we encounter things like this,” Sidortsov said.

Both researchers stressed there is no agenda to the research.

“One of the advantages of running a study like this is we don’t have an ulterior motive. Even if we’re proven wrong in our endeavor, it will be a bummer, but it will still be an important discovery,” Sidortsov said.

He said the pilot study will yield important insight into water control and quality, necessary proximity to transmission lines and other information that can be used for similar projects in other mines in the area. About 20 years ago, Michigan Tech cataloged more than 800 mines in the western Upper Peninsula alone.

However, if all goes well, Scarlett said they hope to use the pilot project as a launch to seek funding for a nationwide project on hydro pumped storage in abandoned mines. Sidortsov said even dry mines could host chemical battery storage or completely flooded mines could house compressed air storage.

“We’re not a developer; we’re not proponents of any kind of technology,” Sidortsov said.

But the researchers do have a certain backdrop in mind for such storage projects.

“The idea is to stick with this post-industrial landscape,” Sidortsov said. “What we’re also trying to do is directly appeal to the policymakers in Michigan.”

The two are examining how such a concept might be monetized, boosted either by state-level tax credits or other financial incentives.

“This can be a transmission resource. This can also be the base around which distributed energy resources can be built,” Sidortsov said. “It gives an opportunity for intermittent resources to be connected to the grid. It also does present opportunities for grid resilience because it’s localized and you’re not depending on one large transmission line.”

But Sidortsov said Michigan Tech will look into the facility performing in several ways, including providing ancillary, capacity, generation and transmission services.

“We’re not bound by a particular use,” Sidortsov said.

The two are also hopeful that mine energy storage could help alleviate customer bills in the Upper Peninsula, which has been subject to expensive energy rates and multiple past system support resource agreements that fund aging coal-fired plants needed to serve the transmission-constrained region.

“We’re representatives of that customer group by virtue of our bank accounts, so the pain is personal,” Sidortsov joked.

Prohibitively high energy costs are also a concern for local governments, Scarlett said. “The leaders of these communities have identified this as one of their major concerns to economic development.”

‘Attractive’ Sites

The researchers still must track down the most recent maps of the mine and figure out what entity — if any — might still have rights to the underground areas. Sidortsov and Scarlett say, so far, they know the rock in which Mather B is situated has “soft” upper layers that were heavily reinforced in the 1970s. The upper levels of the mine might only need to be grouted to create a watertight reservoir, they said.

“Unlike a greenfield site that you would have to study, these mines come with a complete geological and hydrological study. It’s another reason why these sites are so attractive,” Sidortsov said.

He also said the mine’s year-round stable climate is a particular advantage for hydropower design. “You have essentially the same conditions year-round,” Sidortsov said. “With other hydroelectric sites, production varies with snowfall, rainfall … how much ice is on the river. Here, you don’t have that problem.”

The researchers also say the Upper Peninsula’s mines’ historic powerhouses might be adapted to connect the storage to the grid.

Even permitting might prove less of a headache, Scarlett said.

“The rights of way might still be there; you may not have to pay for them,” Scarlett said.

The ultimate goal, Scarlett said, is a “respectful design” in harmony with the original function of the mine’s industrial character. He said a plan that disturbs little while repurposing the mine might allow developers to access funds and credits that states or municipalities dedicate to historic preservation and adaptive reuse of historically important structures.

Sidortsov said the idea so far is receiving a surprising amount of bipartisan support in the state.

“Tim and I were just geeking out, then we quickly discovered it wasn’t just us,” Sidortsov said of the project’s roots.