With a U.S. Court of Appeals ruling on Tuesday, the license granted to Constellation Energy over the controversial Conowingo Dam has been vacated.
According to the decision, the Federal Energy Regulatory Commission had no authority to issue a license based on Maryland’s withdrawal and “waiver” of its Water Quality Certification granted for the Dam in 2018. The state tried to waive the certification in a settlement agreement with the energy company that separated from Exelon Corp. in 2022.
“While we are still reviewing the order, we are surprised and disappointed in the D.C. court’s decision to vacate Conowingo’s license renewal,” said a Constellation spokesperson to Delmarva Now. “No one who cares about clean air and the health of the Chesapeake Bay should be cheering this decision, which potentially jeopardizes the state’s largest source of renewable energy.”
The spokesperson also said the ruling could “disrupt” up to $700 million that Constellation pledged for environmental programs, projects and other payments that directly benefit water quality, aquatic life and citizens living on and near the bay.
The $700 million is divided into $225 million from the settlement agreement with Maryland, up to $300 million from the settlement agreement with the United States Fish and Wildlife Service and includes $175 million from license requirements for recreational facilities and rare, threatened and endangered species protection.
Exelon, and now Constellation, was originally tasked with reducing the amount of nitrogen and phosphorus pollution that flows past the dam annually by millions of pounds that eventually ends up in the Chesapeake Bay. Such pollution contributes to issues including dead spots with little to no oxygen for sea life and lack of sea grass needed by juvenile crabs to replenish their numbers.
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The decision that essentially voids the 50-year license issued in 2021 restarts the cycle of challenges by the utility and others to the Water Quality Certification that Maryland issued before entering the settlement agreement.
Lawyers from the Chesapeake Bay Foundation working on the appeals case included Paul Smail and Brittany Wright along with James Pew of Earthjustice, who represented Waterkeepers Chesapeake.
A temporary win?

“The court’s decision today is a cause for celebration among all who fight for and appreciate clean water. Maryland’s sweetheart deal with Constellation let the utility off the hook for what would have been decades of pollution related to the dam’s operations,” said Alison Prost, the foundation’s Vice President of Environmental Protection and Restoration.
Prost contended Maryland leaders now have the opportunity to directly address the negative downstream impacts of the dam through a new license complete with a state water quality certification.
“We urge the state to use this opportunity to force Constellation to invest in upstream environmental projects that will offset the harm caused by the dam’s presence and protect the Chesapeake Bay for generations to come,” Prost said.
ShoreRivers, an environmental activist organization, echoed those sentiments, saying any agreement without a suitable Water Quality Certification lacked “protections, accountability, and transparency.”
“We applaud the court’s decision to vacate this license and protect our local communities and their fundamental right to clean water,” said Zack Kelleher, a Sassafras Riverkeeper. “The Eastern Shore bears the brunt of the pollution that flows through the Conowingo Dam, creating navigational hazards, shorelines choked with debris, and oyster bars and underwater grass beds smothered with sediment.”
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The grassroots efforts by organizations like ShoreRivers started with educating the public about the long-term implications of an environmentally compromised Bay.
Since 2017, they worked on legislation at the state and federal levels, held and participated in town hall meetings, have given talks around the watershed and done “their best to inform the public about how they could get involved.”
According to Constellation Energy, the dam powers an equivalent of 165,000 homes, prevents 880,000 tons of greenhouse gas emissions annually, clears 600 tons of upstream debris by dam operators annually, provides $273 million in economic benefits throughout Maryland and supports 265 full time equivalent jobs per year.