An asphalt-and-clay pond, the size of a large swimming pool, sits atop a bluff overlooking Lake Michigan, holding enough water to power 1.6 million homes. It’s part of the Ludington Pumped Storage Plant, which works on a simple principle: water is transported from a lower reservoir — in this case, the lake — to an upper reservoir, then discharged downhill via supersized turbines.
Supporters call these systems “the world’s largest batteries” because they store massive amounts of potential energy that can be useful when the power grid is in need.
Pumped storage, according to the hydropower sector, is the best response to a conundrum that has been looming over the shift from fossil fuels to renewable energy to address climate change: where to acquire power when the sun isn’t shining or the wind isn’t blowing.
“I wish we could build 10 more of these. I love ’em,” Eric Gustad, community affairs manager for Consumers Energy, said during a tour of the Ludington facility.
However, the Jackson, Michigan-based utility has no such intentions. Consumers sold another prospective site near the lake years ago due to environmental and logistical concerns, as well as the possibility of billion-dollar expenses. It is now working with co-owner DTE Energy to upgrade the existing plant.
Building a new one “doesn’t make financial sense,” according to Gustad. “Unless we get some help from the state or federal government, I don’t see it happening any time soon.”
Stuck in neutral
The company’s decision exemplifies the difficulties that pumped storage systems face in the United States, where they account for roughly 93 percent of utility-scale energy in reserve. While analysts predict a surge in demand for power storage, the industry has been slow to grow.
The country has 43 pumped storage facilities with a total capacity of 22 gigawatts, equivalent to the production of 22 nuclear power plants. Yet, since 1995, just one small operation has been added, and it’s unclear how many of the more than 90 planned will be able to overcome the economic, regulatory, and logistical obstacles that cause protracted delays.
The Federal Energy Regulatory Commission has granted licenses to three projects, but none of them are in construction. Work on a long-planned Oregon plant is likely to begin in 2023, according to the developers. Before construction can begin, a Montana firm that received a license five years ago requires a utility to run the plant and purchase its storage capacity.
In comparison, more than 60 are currently under construction around the world, primarily in Europe, India, China, and Japan.
Every project is Unique
During a Senate Energy and Natural Resources Committee hearing in January, Malcolm Woolf, head of the National Hydropower Association, claimed that the permitting process is “crazy,” claiming that it includes too many authorities.
Although the FERC approves new facilities and relicenses existing ones, other federal, state, and tribal entities also have a role, according to FERC spokesman Celeste Miller. “Every project is unique. All have various case-specific issues,” she said.
The business is campaigning for a tax credit comparable to that given to solar and wind energy. The tax break is a part of President Joe Biden’s Build Back Better plan, but it is at a stop in Congress.
Pumped storage first appeared in the early 1930s. The majority of the systems, on the other hand, formed decades later to store extra electricity from nuclear power reactors and release it when needed.
The storage facilities also provide a safety net in the event of a power outage. “The lights in Boston didn’t flicker” when a New England nuclear plant went down in 2020, Woolf claimed because two pumped storage units provided backup power.
Nuclear, coal and natural gas facilities can run constantly, but wind and solar plants can’t. Therefore, the market for reserve power is likely to expand. According to the National Renewable Energy Laboratory, storage capacity in the United States might increase fivefold by 2050.
“We’re going to bring hundreds of gigawatts of clean energy onto the grid over the next few years and we need to be able to use that energy wherever and whenever it’s needed,” Energy Secretary Jennifer Granholm said last year.
Location
Engineers from Australia’s National University found more than 600,000 “potentially feasible” pumped storage locations around the world. Thereby, including 32,000 in the US. They could store 100 times the energy needed to maintain a global renewable electricity network using computer mapping.
However, the study did not look into whether or not the sites would meet environmental or cultural protection standards, or whether or not they would be commercially feasible. “Many, if not all,” it admitted on its website, “may out to be unsuitable.”
Pumped storage is unpopular with environmentalists because reservoirs are often constructed by hydropower dams. They obstruct fish passage, degrade water quality, and emit methane, a potent greenhouse gas. In addition, most plants receive water from rivers regularly.
Environmentalists believe the project could ruin wetlands and wildlife habitats, while tribes claim it will encroach on a sacred location.
“What are we willing to sacrifice to get this technology online?” said Bridget Moran, an associate director of American Rivers.
The project would include a cleanup of the filthy lower reservoir area, according to the developers.
The US Department of Energy has established a web-based tool. It is to assist developers in finding the optimal locations for their projects.
Hundreds of abandoned U.S. mines were identified in a recent Michigan Technological University research as potential pumped storage sites. They had top reservoirs at or near the surface and lower reservoirs below ground.
According to the research, they are close enough to transmission and distribution infrastructure and solar and wind generation facilities.
“All these holes in the ground are ready to go,” research co-leader Roman Sidortsov says. He is an associate professor of energy policy.
Some decommissioned mines may be healthier for the environment. But a project in Essex County, New York, has stopped because of worries over water pollution.
Future competitiveness
New technologies are emerging as the market for stored energy expands.
Quidnet Energy, based in Texas, has invented a pumped storage system. It drives water underground, traps it between layers of rock, and then releases it to power turbines. In March, the firm announced a partnership with the city of San Antonio’s municipal utility.
A crane driven by renewable energy was developed by Energy Vault, a Swiss firm, to lift and stack 35-ton bricks. The bricks are lowered by wires that spin a generator when energy is required.
Batteries are now the most competitive alternative to pumped storage systems, which can supply power for eight to sixteen hours. Lithium-ion batteries normally last four hours, but longer-lasting versions are in the works.
“Are we going to get to the point where an eight-hour battery is cheaper than a pumped storage plant? That’s the billion-dollar question,” says Paul Denholm, an analyst with the National Renewable Energy Laboratory.
According to a 2016 Energy Department estimate, the US network could add 36 gigawatts of new pumped storage capacity.
“We don’t think pumped storage is the be-all, end-all but it’s a vital part of our storage future,” says Cameron Schilling. Schilling is the vice president of markets for the hydropower association. “You can’t decarbonize the system without it.”