WISCONSIN DELLS — Decades before the construction of Wisconsin’s first coal-fired generator, an engineer named Magnus Swenson and his partners harnessed the power of the Wisconsin River behind a wall of concrete.
More than a century later, the Kilbourn dam is still churning out electricity, enough to power nearly 5,000 Wisconsin homes last year, one of more than 140 hydroelectric dams that generated more than 4% of Wisconsin’s electricity supply last year — and nearly half of all renewable energy.
“We are the original renewables,” said Amanda Blank, site manager for hydroelectric and gas operations at Alliant Energy, which owns the Kilbourn dam along with the larger Prairie du Sac dam just downriver. “We plan to be here for a long time. We also add a lot to our communities.”
Recognizing the growing threat of climate change, conservation organizations that have long opposed dams for the damage they inflict on rivers have begun to embrace hydroelectricity as a key to a clean energy future.
Yet it’s been decades since the construction of a new hydroelectric dam in Wisconsin, and the steep up-front costs, strict regulations and significant environmental impacts make hydroelectricity a poor candidate to replace increasingly inefficient and dirty fossil fuel.
Across 15 states and one Canadian province, the Midwestern grid operator has received requests to study just three hydroelectric projects with a combined capacity of 114 megawatts. By comparison, there are nearly 98,000 megawatts of solar, wind and battery projects under consideration.
“Dams are inherently expensive to build,” said Ian Baird, a UW-Madison geographer who studies hydropower. “The economics are just not there, even if you’re really concerned about climate change. Hydropower is not the answer.”
But with no fuel costs or toxic byproducts — plus the ability to store and release energy on demand — this aging infrastructure could play a supporting role in the clean energy transition.
Not so clean
While hydroelectricity is considered renewable energy under state law, it’s not without significant environmental impacts, altering water flow and temperatures, impeding the movement of aquatic species, even leading to extinction.
“We are firm believers that it’s healthier for our rivers and streams to be free-flowing,” said Allison Werner, policy and advocacy director for the Wisconsin River Alliance.
There’s also a growing body of research pointing to reservoirs created by dams as a source of heat-trapping gases such as methane that are released by decaying underwater vegetation, especially in the first decades after construction.
“It’s not that hydropower is totally benign,” Baird said.
After a half-century of fighting dams, a group of conservation organizations last month reached a truce with the hydropower industry, agreeing to work together to generate more clean energy from existing dams while working to mitigate the environmental impacts.
Completed in 1922, the 3.6-megawatt Pine River dam is one of three dams along the Wisconsin-Michigan that We Energies agreed to remove as part of a historic 1997 deal with federal, state and nonprofit agencies.
Two and a half years in the making, the agreement, negotiated by groups including the Union of Concerned Scientists, the World Wildlife Fund and American Rivers, reflects a recognition that climate change represents an even greater ecological threat and that hydroelectricity will play a key role in integrating variable clean energy sources like wind and solar.
“To rapidly and substantially decarbonize the nation’s electricity system, the parties recognize the role that U.S. hydropower plays as an important renewable energy resource,” the agreement states. “At the same time, our nation’s waterways, and the biodiversity and ecosystem services they sustain, are vulnerable to the compounding factors of a changing climate, habitat loss, and alteration of river processes.”
The agreement calls for removing dams that are obsolete or have environmental impacts that can’t be mitigated, rehabilitating others to address safety concerns while retrofitting existing dams to generate more power and potentially adding generation to some of the more than 80,000 dams that serve other purposes.
Jose Zayas, the former director of the Wind and Water Power Technologies Office of the federal Department of Energy and a participant in the negotiations, said the agreement is critical to preserving and expanding hydroelectric power, even if it won’t result in a flurry of construction projects.
“We’re not going to see the large-type infrastructure like Niagara or the Hoover dam. Those opportunities have been exploited in the U.S.,” Zayas said. “Only about 3% of the nation’s dams actually have power. … We believe there’s quite a bit of opportunity to add generation to that existing mission.”
Small but plentiful
The world’s first hydroelectric power plant was built in 1882 on the Fox River near Appleton, supplying electricity for a nearby home and paper mill.
Today only three states — California, New York and Maine — have more hydroelectric dams than Wisconsin, according to the U.S. Army Corps of Engineers’ inventory of dams.
But with Wisconsin’s relatively flat landscape, the generating capacity of its dams is relatively small, about 750 megawatts combined from the 144 dams in the Department of Natural Resources’ database.
That’s about the equivalent of one modern natural gas plant.
The state’s largest hydroelectric plant, Xcel Energy’s Jim Falls dam on the Chippewa River, is licensed for 49 megawatts, about a third the capacity of the state’s first large-scale solar plant, which started operation earlier this month in Manitowoc County.
The average dam is about 5 megawatts, equivalent to two modern wind turbines.
Though some have been rebuilt over the years, most have been in place for more than a century.
New power from old assets
The federal Department of Energy estimates the nation could increase its hydropower capacity nearly 50% without building a single new dam.
A 2012 study identified 12,000 megawatts of potential capacity — about a 15% increase — by adding turbines and generators to existing dams that provide flood control, aid navigation or support water supplies.
About two-thirds of that potential could be achieved with just 100 dams, mostly Corps of Engineers structures like those that maintain a 9-foot deep channel for barges on rivers like the Mississippi. The study estimates the Upper Mississippi River basin could generate enough energy to supply more than 1.1 million average Wisconsin homes.
A 2016 Department of Energy study identified an even larger role for pumped storage, in which water is pumped into elevated reservoirs during times of excess generation and then released to generate electricity when demand is high, essentially functioning like a natural battery that could be paired with clean energy sources like wind and solar.
Together, the study estimated these new hydroelectric sources could power 35 million homes by 2050, saving billions of dollars in avoided costs associated with climate change.
Though there’s greater potential downstream, locks and dams near Alma, Trempealeau, La Crosse and Genoa were among the top 100, with potential capacities between 20 and 40 megawatts each.
“It’s something that’s often talked about in the past tense,” said Zayas, now an executive with Eagle Creek Renewable Energy, which operates several dams in Wisconsin. “The reality is it’s something that’s ongoing.”
Yet past efforts to install generators on the Mississippi River have fizzled.
In 2011, the Federal Energy Regulatory Commission granted a Boston startup a license to develop hydroelectric generators at nine lock and dam sites, which the company said would generate enough electricity for 65,000 homes. The following year another company received a license for a 5-megawatt generator on a Corps of Engineers dam in Genoa.
Both companies surrendered their permits in 2012 citing technical and market conditions.
The only active preliminary permit for hydropower on the Mississippi River is for a 6-megawatt underwater turbine project in Louisiana. The company, Pioneer Valley Renewables, told FERC in May that it has been unable to secure funding for the project.
In a state that’s well watered but vertically challenged, most of the nearly 4,000 non-powered dams simply don’t have the combination of flow and hydraulic head — the difference in water levels — needed to create substantial power.
And efforts to repower old dams don’t always work out.
In 2011, Western Technical College purchased a dam on the La Crosse River that hadn’t produced power in more than 40 years and invested about $4 million in an effort to promote clean energy.
This fall, the college agreed to sell the Angelo dam for $80,000 to a private hydroelectric company, citing growing costs and liabilities as well as lack of student interest in a hydropower curriculum.
“It happens with villages and municipalities,” said Chris Cutts, managing partner of ReNew Hydro Power, the company seeking to take over the license. “It’s not their business… It’s a tough row to hoe unless it’s your career.”
Fixtures of the landscape
While supporting development of new hydropower generation, conservation groups and the hydropower industry agreed to look for opportunities to remove those dams that aren’t providing clear benefits or can’t be cost-effectively repaired.
But getting rid of dams isn’t so easy, especially when they have become part of the landscape.
JP Brummond, president of business planning for Alliant, notes the Prairie du Sac dam creates Lake Wisconsin, while Kilbourn raised water levels in the Dells, making some tourist areas more accessible by boat.
“It’s a bigger question than just restoring the river,” he said. “It’s an economic question, too.”
Last year the city of River Falls voted to remove two dams that supply about 2% of the city’s electricity needs in an effort to develop a 7-mile stretch of the Kinnickinnic River, which was first dammed in 1867.
Mike Page, president of the Friends of the Kinni and a former city council member, said removing the dams will reduce sediment buildup and lower the water temperature to ensure that trout can thrive while restoring a natural 70-foot rapids in the heart of town.
“That’s just spectacular. It’s a huge opportunity for us to restore this natural feature,” Page said. “The choice is fairly obvious.”
Page said resistance to change is the biggest barrier to dam removal.
“They’re kind of seen as fixtures of the landscape that have been there forever,” he said. “Removing them seems like this outlandish idea.”