Maine dams face an uncertain future

The Ellsworth Dam, nestled just upstream from the picturesque Union River Bridge in downtown Ellsworth, is easy to miss, the extent of its towering facade hidden from passing motorists by foliage and a bend in the river. Flow to the dam is controlled by another dam upstream.
Without the two dams, which make up the Ellsworth Hydroelectric Project, the community would look vastly different than it does today: the two lakes behind it would turn to rivers, and those with lakefront homes would have hundreds of feet between them and the water.
But their legacy on the landscape does not guarantee its long-term operation. The Ellsworth Dam’s corporate owners are enveloped in a years-long legal battle for a state water quality certification required to keep its turbines spinning for another few decades, a battle that is currently in the Maine Supreme Judicial Court.
The strife in Ellsworth is indicative of larger questions that Brookfield, the Canadian multinational investment firm that owns most Maine hydroelectric dams, including the ones in Ellsworth, and communities across the state are confronting: as Maine’s aging dams require significant investments to meet stringent environmental standards and continue operating, will their owners double-down and do what it takes to keep them running, or will state influence and local opposition send them to retirement?
These complex decisions are more urgent than ever. Maine must fulfill its quickly approaching renewable energy goals, and is pursuing more wind and solar projects to do so.
Meanwhile, state policies on water quality and fish passage are more influential than ever, and proponents of aquatic habitat restoration are galvanizing to flood public comment forums on dam operation licenses with pro-dam removal messaging.
What happens with Maine’s remaining dams could have dramatic implications for the communities that have been shaped by these structures for centuries and for the state’s renewable energy portfolio. 
Even as the state makes gains elsewhere, hydro remains the linchpin of renewable energy in Maine, providing 30 percent of the state’s renewable generation last year and consistently outperforming all other renewable energy sources.
The dozens of active hydroelectric dams in the state have long-dominated Maine’s renewable energy portfolio, before benchmarks for renewable energy were even set. But at an average age of 104 years old, they have been losing out to investments in newer technologies.
Wind energy surpassed hydroelectric power as Maine’s largest source of in-state renewable electricity for the first time in 2021 and, alongside solar, is poised for significant expansion under state law.
The 124 hydropower dams in Maine, meanwhile, are squeezing out the electricity they’re capable of while their corporate owners are saddled with mounting operating costs.
Days after the state released a draft of its road map to “clean electricity” comprising 100 percent of demand by 2040, all signs point toward wind, battery systems and solar lining the final route. 
Maine’s hydroelectric prominence comes from the more than 30,000 miles of rivers within state boundaries, where more than 60 of those waterways bleed into the Atlantic.
While periodic drought, inflamed by climate change, has threatened their supply in recent years, Maine rivers are fueled by a relatively consistent amount of precipitation year-round (between 40 and 50 inches annually) and snowpack that recharges the lakes and mountain streams the rivers pull from.
For decades, hydroelectric plants have provided Maine with a steady, reliable source of renewable electricity.
In 2023, Maine’s 51 hydroelectric plants generated 726 megawatts of fossil fuel-free electricity, roughly 31 percent of the state’s overall electricity generation and around 47 percent of its renewable generation. That figure has stayed largely steady for decades.
Renewable sources — which include hydro, wind, solar, wood and biomass — comprised 65 percent of Maine’s in-state electricity generation in 2023, according to the U.S. Energy Information Administration. That ratio will have to increase to 80 percent by 2030 and 100 percent by 2050 under a bipartisan law signed by Gov. Janet Mills in 2019.
To advocates, the appeal of hydropower is straightforward: Maine rivers, recharged by the trillions of gallons of precipitation that falls on the state each year, are able to keep turbines spinning day and night, even when flows are lowest in the drier late summer and early fall. 
Dams can also ease the grid back online after widespread blackouts because they don’t need a jolt of electricity to start generating again. Those with large reservoirs serve as giant aquatic batteries, ramping up generation by allowing more and more of the penned-in water behind the dams through their floodgates and spinning the turbines below (compared with run-of-the-river dams, which have a flow more consistent with the river’s current).
That function is crucial when electricity demand is highest and other renewable energy sources falter, like during cloudy, windless Maine winter days when people flip on their light switches after returning home from work.
In a future where Maine looks to ease reliance on its natural gas plants, which provide a similarly reliable source of electricity but produce planet-warming gasses, hydropower remains the state’s best emissions-free option, according to Tom Welch, former chair of the Maine Public Utilities Commission.
“Hydro has played a reasonably significant role in the past, and getting as much production as you can out of hydro facilities is important, because once they’re up and running, they’re very beneficial,” Welch told The Maine Monitor. “They can be [easily] dispatched and are basically carbon free.”
Making the plants that exist as efficient as possible, Welch said, is the most cost-effective, low-carbon way to build a more reliable, resilient grid and move toward renewable energy goals.
For Welch, the reasons are obvious: The dams are already there (and in Maine’s case, often have been for more than a century) and wouldn’t cost as much as bringing an entirely new energy source online. 
“Spending some state money to increase the efficiency of dams that we’re going to permit to stay is quite possibly a cost effective way of reaching environmental goals,” Welch said. “If you can get 10 megawatts for a very low price, then that’s 10 megawatts you don’t have to pay someone else to get.”
Much of New England is also heavily reliant on hydroelectric power to meet its energy needs. A significant portion of that electricity comes down through transmission lines from Quebec and its vast network of 61 hydropower plants across the province. Hydro-Quebec, the provincial government-owned corporation that operates Quebec’s dams, provided 24 percent of Vermont’s electricity in 2022, more than any other source.
A report on Maine’s Renewable Portfolio Standard recommended that Maine support existing renewable energy projects when feasible, especially those facing costly age-related equipment failures that can be salvaged with larger investments in maintenance and refurbishment.
Maine’s most significant and recent policy that benefited hydroelectric dam owners came in 2019, when the Legislature changed the classification of credits for hydro-produced electricity on the renewable energy market to a more valuable credit class. 
Overall, Maine policymakers have been reluctant to make more direct investments in hydropower. The program tasked with regulating non-federal dams is vastly underfunded and understaffed, according to a recent report, with just two engineers to ensure the safety of more than 500 dams. 
And despite the 2019 renewable energy credit update, larger dams still aren’t eligible for the more valuable credit class, all while generous subsidies are flowing to the offshore wind sector. Also in 2019, lawmakers voted to keep a 100-megawatt cap on hydropower plants, which would have allowed hydropower produced in Canada to qualify toward Maine’s renewable portfolio standards. (Wind and solar are not subject to such a cap.) 
A recent boon in federal funding, however, could provide the support Maine dams need to clear regulatory hurdles.
The Biden administration announced in early September that 21 privately owned and operated hydroelectric projects in Maine would receive $33.8 million in Bipartisan Infrastructure Law funding for standard maintenance, fish passage upgrades and energy efficiency improvements — the largest investment in New England.
The money is an indication that federal officials expect that hydropower will continue to play an important role in the energy landscape for decades to come, and comes at a crucial time in the dam’s long term management. 
By the end of the decade, nearly 135 dams in the Northeast U.S. are expected to go through federal relicensing, according to former University of Maine energy researcher Emma Fox. Northeast dams would account for roughly 46 percent of total relicensing applications nationwide, more than any other region in the country.
Whether the Federal Energy Regulatory Commission — the federal hydropower licensing authority — approves those applications will determine whether dams can operate for the next 30 to 50 years. 
The commission’s decisions depend on the dams’ abilities to meet stringent water quality standards and pass seagoing fish to and from their upstream spawning grounds, meaning the Department of Energy funds could help make or break the dams’ long-term operations.
The cost for upgrading Shawmut Dam on the lower Kennebec River to meet FERC fish passage requirements is estimated by FERC to be around $6.3 million.
That same dam could receive $4.8 million through the Bipartisan Infrastructure Law funding. Shawmut’s owner, Brookfield Renewable, and the Department of Energy would not provide details on what type of project the grant would be used for. Shawmut is in the midst of a lengthy relicensing process.
“These investments will preserve and sustain existing hydro resources in Maine, which will continue to serve an important role in Maine’s clean energy mix, in addition to wind, solar, biomass, and energy storage,” said Afton Vigue, spokesperson for the Governor’s Energy Office. “From a policy standpoint, GEO’s goal is to maintain the current stock of Maine hydro facilities.”
Early European settlers arriving in the 1600s quickly set about harnessing energy from Maine rivers to saw lumber, grind grains and weave together textiles, displacing Indigenous people who for generations relied on the watershed’s natural forms.
By the 1860s then-Maine Gov. Joshua L. Chamberlain wanted to know just how much mechanical power flowed down from the Appalachian mountains into the Atlantic each day and how the state could best leverage it.
Chamberlain and the Legislature ordered Walter Wells, superintendent for the Maine Hydrographic Survey, to map each major river’s cascades and calculate their corresponding mechanical potential in horsepower, creating the state’s first comprehensive estimate of its hydropower reserves.
When Wells returned to the Legislature two years later, his agency’s newfound revelations filled him with so much optimism that nearly every word on hydropower’s prospect in his 1869 report dripped with pride and jubilation.
“Our grand resource is of a kind that will never fail or become materially modified, because it is based upon the unchanging features and sustained by the perpetually recuperative processes of nature,” Wells wrote.
Whereas the coal reserves of Pennsylvania or oil reserves of other states may “ultimately fail, and many of them speedily fail,” Wells argued that Maine’s rivers were a more productive power source that could generate wealth indefinitely, and that its leaders should do everything possible to actualize the rivers’ potential. 
What followed was a period of growth accelerated by the development of hydroelectric power. In 1880, the first hydroelectric dam powered a store and theater in Grand Rapids, Michigan. A year later another plant harnessed the Niagara River’s ferocious current to illuminate the city streets above the falls — the first such large-scale facility in the country.
These breakthrough innovations extended the energy of Maine rivers beyond their banks, starting in 1899 with a small facility off the Kennebec River that provided electricity to 100 customers in nearby Oakland. 
The facility’s creator, electrical engineer Walter Wyman, went on to lead the proliferation of hydroelectric dams throughout Maine. Wyman’s utility company, now known as Central Maine Power, began absorbing mills on the Androscoggin River and elsewhere on the Kennebec, converting them into hydroelectric dams and sending electricity zigzagging across the state through transmission lines.
It didn’t take long until the most productive sites that Wells identified in his 1869 report were all dammed up. In 1930, CMP began purchasing land and displacing locals to build larger hydroelectric projects on the confluences of state waterways, artificially inflating places like Flagstaff Lake, which was only a drop in a bucket compared to its current size. 
This period of productivity was marked by the completion of the Harris Station hydroelectric plant on the upper Kennebec River in 1955, which remains one of the state’s largest dams.
The industry has been aging and contracting in the decades since.
Between 1912 and 2024, Maine lost 50 hydroelectric dams, according to data from environmental nonprofit American Rivers, though the state still has hundreds today, both active and relics. At an average age of 104 years, Maine’s active hydropower dams are some of the oldest in the country, according to Fox, formerly of UMaine.
The roughly 730 megawatts of power capacity that Maine’s hydroelectric dams currently provide has remained largely unchanged since 1998, and little opportunity exists to expand their generation capacity.
According to a 2015 study commissioned by the Governor’s Energy Office, “only 45 sites with 55 MW of potential capacity showed significant development potential.” Consider the delayed return on investment that such a development would take, and hydro’s expansion becomes even less appetizing in Maine, especially as grants flow to other energy sources.
“Compared to other types of renewable energy, conventional hydropower development is capital intensive and has a long payback period, making the economics of most new projects marginal,” the authors wrote.
Hydro’s consistent output lays the foundation for Maine’s renewable energy goals, but its proportion of generation is projected to shrink in comparison to other sources.
Maine is currently betting that it will meet those goals with the broad expansion of wind and solar power. Separate legislative mandates guide the state to develop 3,000 megawatts of offshore wind capacity by 2040 and 750 megawatts of small-scale energy developments, namely solar arrays.
Those new interconnections to the grid coincide with a goal to add 400 megawatts battery storage capacity, infrastructure required to bottle up excess wind and solar energy then bused to quench a thirsty grid when winds die or the sun doesn’t shine, especially during Maine’s winters.
The most recent draft of the Governor’s Energy Office Maine Pathways to 2040 plan describes maintaining hydropower’s status quo and prioritizing battery storage as the solution to building the state’s long-term energy reserves.
The Department of Energy awarded $147 million grant funding to the developer of an 85 megawatt battery project in Lincoln in August, which is being touted as the “world’s largest” multi-day energy storage facility. In southern Maine, construction began in April on a separate 175 megawatt energy storage facility in Gorham that is expected to come online in mid-2025.
Maine currently has 60 megawatts of grid-connected energy storage at six locations, according to Vigue and the GEO, so the input from the Gorham facility will be a significant step toward the Legislature’s goal to develop 400 megawatts by 2030.
Complicating the state’s plans for small-scale energy developments, however, is the scattered pushback of Maine communities against solar development, resulting in solar moratoria across the state that have halted projects and increased their cost.
Solar developers are also concerned that proposed rules from state environmental agencies designed to set aside and protect forest or farmlands from solar arrays could further hamper the industry, which is already dealing with high costs and long lines to connect their solar projects to the state’s electrical grid.
“When we account for the compounding effect of the Department of Agriculture, Conservation and Forestry’s (DACF) parallel rulemaking, it is hard to see a future for utility-scale solar in Maine,” wrote Robert Cleaves of Dirigo Solar in comments to state regulators.
Maine’s plans for offshore wind development, meanwhile, hit a snag when the state was passed over in October for a $456 million federal grant that would cover most of the costs for a planned port to assemble turbines on Sears Island.
Two companies purchased four lease areas in the Gulf of Maine that could be developed for up to 6.8 gigawatts of offshore wind power, Canary Media reported on Oct. 29. Four other lease areas, however, went unsold in that same auction, and the leases were sold at comparatively low prices to others in the northeast — a sign of “deep industry malaise,” Reuters reported that same day.
Complicating matters further is President-elect Donald Trump’s negative views toward offshore wind, made evident in his celebration of the recent cancellation of a wind project off the New Jersey coast, and his pledge to gut federal renewable energy funding. 
But Maine hasn’t given up on procuring the federal funding needed for the port on Sears Island.
“We are still awaiting a decision about federal grant funding to help with our ongoing design and permitting efforts,” Maine Department of Transportation Commissioner Bruce Van Note said in a statement in October. “Maine has a once-in-a-lifetime opportunity to develop a port facility to create good-paying jobs while serving the entire region as we harness abundant clean wind energy in the Gulf of Maine.”
Though it’s not without controversy — especially the 100-acre port planned for an undeveloped tract of Sears Island, much of which is currently a nature preserve — wind has been winning over public opinion in Maine compared to the backslide against hydro.
Anti-dam sentiment in North America largely arose in the 1970s with the modern environmentalism movement to clean up American rivers and the 1971 proposal of the James Bay Project in Canada, a colossal hydroelectric development in northern Quebec. 
The Quebec provincial government developed plans for the project without consulting the local northern Cree and Inuit communities beforehand, sparking immense backlash when Quebec unveiled blueprints that depicted the mass-inundation of thousands of square miles of Indigenous lands and hunting grounds.
Indigenous leaders reacted swiftly and filed a lawsuit to halt the project’s development. Their opposition culminated in a multi-million dollar settlement with the province and its corporation, Hydro-Quebec, allowing the project to go forward, uprooting an entire village and unleashing mercury into native fish and wildlife.
When Quebec returned in 1988 with yet another massive hydroelectric project proposal on the Great Whale River, Indigenous opposition was even more widespread and successful, marked by a five-week canoe trip of Cree and Inuit paddlers from northern Quebec to New York City. Indigenous protests ultimately gained sympathy from New York officials, who backed out of their investment in the project, depriving Hydro-Quebec of necessary funding and killing the proposal.
Opposition to Hydro-Quebec’s dams, which contribute a large portion of electricity to New England’s grid today, grew in Maine in response to the New England Clean Energy Connect Project, commonly known as the CMP corridor, a transmission line designed to bring electricity from Hydro-Quebec to the New England grid. The project is under construction after years of fights. 
Dams like Shawmut have also been increasingly criticized for the barriers they pose for migrating fish. Maine waterways are seen as the last viable habitat for the endangered Atlantic salmon in the United States, and environmental groups, Wabanaki officials and recreationists across the state have been advocating removing any impediments to their passage.
Landis Hudson, head of the environmental nonprofit Maine Rivers, primarily focuses on the removal of “dinky” dams that are no longer producing electricity in order to restore access for native seagoing fish to upstream spawning grounds. 
But because of the dire condition that populations of Maine species like alewife, Atlantic salmon and American eel are in, she believes it’s critical to weigh the energy contributions of Shawmut and other low-river dams close to the ocean — which most immediately halt fish on their journeys upstream — against dams’ ecological impacts.
“We have an obligation to do what we can to improve the health and vitality of our rivers, because we are so closely connected to such a tremendously important marine resource,” Hudson said. For each dam, she said, people must ask: “OK, why is this one here? What value does it have? What are the ecological impacts? And how do we value keeping versus removing a dam?”
Campaigns for dam removal in Maine have picked up momentum over the past two decades. In 2008, a coalition headed by the Penobscot Nation, environmental nonprofits and fish advocates raised millions to purchase three prominent dams on the Penobscot River. A few years later, the coalition removed two, restoring roughly 2,000 miles of habitat for aquatic creatures.
Removal is rarely straightforward, however. The coalition fighting for fish passage on the Penobscot River faced opposition from residents in Howland who were against removal of the third dam, so they compromised and added a fish bypass instead.
A similar situation unfolded in Dover-Foxcroft earlier this year, where residents rejected a referendum to remove a town-owned dam on the Piscataquis River that no longer produces electricity, instead favoring a potentially more expensive path to maintain it.
Even though federal officials recommended that Shawmut, on the Kennebec River, be relicensed with added infrastructure for fish passage, dissatisfaction was evident at its federal relicensing hearing in May. Relicensing has never been a layup for Maine dams, and the state has wavered in recent years on its support for them.
It was only four years ago that the Mills administration recommended removing Shawmut, a separate upstream dam, and considering the removal of two neighboring dams on the lower Kennebec River. The loss of those dams’ renewable electricity contributions, which account for 0.43 percent of the state’s annual electricity generation, the administration argued, could instead be replaced by new clean energy developments, like grid-scale solar.
The Department of Marine Resource only backed away from its proposal after Sappi officials said removal would cause its paper mill in Skowhegan to close and Brookfield Renewable, the dams’ owner and a subsidiary of a global investment firm whose dams provide 87 percent of all hydropower in Maine, filed a lawsuit.
A precedent for dam removal was set just downstream of Shawmut in 1997, when FERC commissioners voted to remove Edwards Dam to help restore fish populations, the first order of its kind in the agency’s history and a watershed moment for the Kennebec River and dam removal efforts nationwide.
The efficacy of dam fish passages and federal requirements for their installation have come a long way, Hudson said, but at the end of the day, “The life in rivers is largely invisible. We can guess when the fish are there, but it’s hard to know what’s going on. We do know that the life that lives in our rivers, historically, is largely gone.”
The commission’s decision on Edwards shows that no dam is a guaranteed shoo-in through FERC’s complex relicensing process. Upstate at the Ellsworth Hydroelectric Project on the Union River, Brookfield is entering its fifth year fighting for a state water quality certification that FERC requires for the dam to continue operating, a battle now unfolding in the Maine Supreme Judicial Court.
A 2019 federal district court decision gave states more influence over the dam licensing process by requiring that state regulators certify that a dam does not have detrimental environmental effects on the water body it sits on. 
Whereas in years prior, states could give dam owners time and the opportunity to revise their applications for a water quality certification if it was incomplete or indicated poor environmental impacts, the new precedent requires states to accept or reject applications within one year of their submission — or give up the right to weigh-in on the dams’ environmental impacts altogether.
In the case of the dams in Ellsworth, the Maine Department of Environmental Protection denied a Brookfield subsidiary its water quality certification because of a failure to account for aquatic habitat on Graham Lake upstream and the Union River below, according to the department. Because the application was “denied without prejudice,” however, Brookfield still has a chance to submit a new application for approval. 
Where Brookfield Renewable, the state’s lead dam owner, draws the line on its relicensing and operating expenses remains to be seen. 
A company spokesperson declined an interview, but said the Department of Energy grant awards are a sign of Brookfield Renewable’s long-term investment in Maine, stating, “We are proud to play a role in supplying Maine with the power required to meet increasing electricity demand while also contributing to the state’s journey toward achieving net zero by 2040.” 
The fate of a dam never impacts just one group of people. In removal, advocates see a chance to return sea-run fish, residents see mudflats, and companies see lost profits. In many cases, for communities whose residents have existed along the reservoirs created by dams for generations, their disappearance now would be almost as unfathomable as the displacement their creation caused decades ago. 
“It’s right in the middle of our community,” said Tom Lizotte, who advocated for removing a dam in Dover-Foxcroft earlier this year. Residents voted 558 to 411 to keep it. “That’s what people have known.”
This story was originally published by The Maine Monitor, a nonprofit and nonpartisan news organization. To get regular coverage from the Monitor, sign up for a free Monitor newsletter here.