Inside the Sault hydro-electric plant in Michigan’s Upper Peninsula, 74 turbines are spinning and generating power for thousands of homes in the region.
This narrow plant is a quarter-mile long and its red sandstone bricks harken back to the Gilded Age when the plant first opened in 1902.
“It’s been running pretty much 24/7, 365 since then,” said Roger Line, a director of generation with the Cloverland Electric Cooperative, which owns the plant today.
The newest turbines are 113 years old and run smoothly, but Line said Cloverland considered shutting the plant down.
“If you were to buy the same amount of energy today, you could probably get it cheaper elsewhere,” he said.
Ultimately, the company kept the plant open. Line said it’s not too expensive to run and still generates a reliable flow of energy. Yet this back-and-forth on whether to keep hydro online isn’t uncommon.
A 2022 survey conducted by an engineering consulting firm found that about 36% of hydro operators in the U.S. were actively thinking about decommissioning their facilities.
Operators also noted they were “very concerned” about low energy prices, dam and public safety requirements that raise costs and the long, expensive process of renewing operating licenses.
Federal licensing
Unlike wind or solar projects, hydro facilities require a federal license that must be renewed every 30-50 years. Because water is a shared resource, plants often have to deal with dozens of federal, state, tribal and local authorities.
It can be a bureaucratic nightmare, according to Malcolm Woolf, the president of the National Hydropower Association. He said it takes eight years on average for a facility to relicense, and the process can sometimes drag on for more than a decade.
“Part of what makes the hydropower licensing so maddening, is that there’s no agency in control,” Woolf said. “If one of the dozens of agencies misses its statutory requirements, there’s nothing anyone else can do about it but wait.”
Woolf said licensing should be streamlined. He points out that there is no dispute resolution process if agencies impose different standards, causing projects to “languish.”
“And the requirements can be contradictory — have no more than 2 feet of water for this species. Have no less than 3 feet of water for this other species,” Woolf said. “It's like, well, we can't comply with both.”
The "Big Beautiful Bill" that recently passed Congress spared the hydro industry from losing out on tax credits, though a draft version in the U.S. House had initially put them on the chopping block.
In a written statement, Woolf described the legislation as a "life-saver" for the hydropower sector.
"The final version of the 'One Big, Beautiful Bill' preserves the full value of the (Inflation Reduction Act) tax credits for hydropower and other water power technologies that begin construction by the end of 2033," he said. "It also maintains elective pay provisions, allowing public power and cooperatives to leverage these credits ... "
Hydro over the years
The Federal Energy Regulatory Commission, which regulates hydroelectric operations, does not keep track of historical license data, so it’s difficult to know exactly how many hydroelectric facilities have gone offline. In the last 15 years, Woolf said 68 facilities have voluntarily surrendered their licenses, though most of them were small-scale operations.
Most facilities were built in the late 19th to mid-20th centuries, and today the average age is 64 years old.
Caitlin Grady, a civil engineer and associate professor of engineering with the George Washington University, said the overall footprint has generally been stable.
Hydropower still accounts for around 6% of the nation’s electricity generation and supports roughly 25 million Americans.
While the hydro industry may not have the same ambitions for growth like wind and solar, Grady said it’s essential to national energy production, especially if we want to cut down on emissions.
“Without major changes in nuclear or hydro, we will not have a sustainable grid with just solar and wind unless we're also building a ton of batteries,” Grady said, “and I mean, tons and tons and tons of batteries.”
Hydro holds the coveted black start capability that allows operators to quickly restore power in the event of a grid shutdown, which Grady compares to flipping a switch on a fuse box.
“In the event of something happening, whether it’s related to climate change, or terrorists or cyber-hacks, anything, you have to have a way to turn [the grid] back on quickly,” she said.
And no one, Grady said, is pitching new hydro developments that require damming up rivers.
“When we originally built a bunch of dams in the early 1900s, we didn't care a lot about the environment or the people we were harming,” Grady said. “It was an era of building lots of infrastructure without thinking through the consequences.”
Instead, Grady said grid reliability and energy output could be expanded by adding turbines to existing dams or investing in modern pumped storage that uses water and gravity as a battery.
Standing the test of time
People have been using water as a source of power for at least 2,000 years, when water mills would crush grain and break ore. And century-old hydroelectric plants continue to churn out power.
The Keokuk Renewable Center, which sits on the Mississippi River, near Iowa, Illinois and Missouri, has been business as usual since 1913. Brad Todd, with Ameren Missouri, said there’s no plan to decommission Keokuk, which supplies electricity to around 75,000 homes a year.
“It's great for the customers, it's safe, it's efficient and Ameren plans on keeping ours around basically forever if we can,” Todd said.
Todd said Ameren has spent the last decade upgrading its fleet with newer, more energy-efficient turbines.
The Cloverland plant in Michigan is looking to make that switch and eventually start phasing out its old equipment to get the most bang for their buck.
With some equipment dating back 128 years, operators can’t exactly order new parts online. Instead, a small team creates custom parts in a repair shop in the plant.
Line said everyone who works at the plant starts as a technician, to get a feel for the historic facility and its quirks.
“You're carrying that knowledge on to the next person, to the next stage,” he said. “That's how we can maintain a quarter-mile-long building that's over a hundred years old fairly efficiently. So we take a lot of pride in that."
This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest. It reports on food systems, agriculture and rural issues.