Maryland Governor Wes Moore has announced a $340 million agreement between the US state and Constellation Energy that clears the way for the long-term re-licensing and continued operation of the 573MW Conowingo Dam, the largest source of renewable power in Maryland.
The agreement, reached in coordination with Waterkeepers Chesapeake and the Lower Susquehanna Riverkeeper Association, establishes enforceable water quality standards under a new Revised Water Quality Certification issued by the Maryland Department of the Environment (MDE). It resolves years of litigation and ensures continued operation of the nearly century-old hydroelectric facility while funding major environmental improvements along the Susquehanna River and Chesapeake Bay.
“The Chesapeake Bay is the keystone to Maryland’s prosperity,” said Gov. Moore. “This agreement will lead to real improvements in water quality in the biggest tributary of the Chesapeake Bay, while securing the future of one of our state’s largest clean energy producers.”
Under the agreement, Constellation will fund more than $340 million in operational and environmental investments, including:
- $87.6 million for pollution reduction, shoreline restoration, and fish habitat improvements.
- $77.8 million for trash and debris removal, expanding efforts that currently remove about 600 tons of material annually.
- $28 million for fish and eel passage upgrades.
- $23.3 million to build and operate a freshwater mussel hatchery.
- $18.7 million for dredging and sediment management studies.
- $9.4 million for invasive species control.
The deal also formalises an oversight role for Waterkeepers Chesapeake and the Lower Susquehanna Riverkeeper Association in implementation and monitoring.
Attorney General Anthony Brown called the settlement “a historic agreement [that] ensures our children and grandchildren will inherit a Chesapeake Bay and Susquehanna River that are cleaner and healthier than they are today.”
The agreement follows years of regulatory uncertainty. An initial certification issued in 2018 led to a 2019 settlement valued at $230 million, but the terms were later vacated after an appeals court voided the dam’s 50-year federal license in 2022. The new framework – developed through mediation and a public comment process – will be submitted to the Federal Energy Regulatory Commission (FERC) to support the dam’s renewed license.
“With this agreement, we are protecting clean water and vibrant ecosystems for generations to come while supporting jobs, commerce, and energy security,” said MDE Secretary Serena McIlwain.
Constellation Energy President and CEO Joe Dominguez said the deal reinforces the company’s long-term investment in clean generation. “The Susquehanna watershed is home to one of the largest concentrations of clean energy generation in America, and Constellation is proud to build on that legacy,” Dominguez said. “We’ve invested more than $1 billion in Maryland clean energy projects over the past decade, and we will never ask Maryland families to bear business risks that we won’t.”
Environmental groups that once opposed the 2019 settlement endorsed the revised framework. “Today’s agreement marks a new era for the dam and a new commitment for clean water,” said Robin Broder, Acting Executive Director of Waterkeepers Chesapeake.
Ted Evgeniadis, Lower Susquehanna Riverkeeper, said the agreement “improves water quality and protects aquatic species for the next 50 years.”
Once the revised certification is incorporated into Conowingo’s FERC license, the state will be responsible for enforcement of the terms.
Governor Moore’s FY2026 budget includes an additional $400 million for Chesapeake Bay restoration and clean water projects. Earlier this year, he signed the Chesapeake Bay Legacy Act, expanding funding for sustainable farming, oyster restoration, and nutrient reduction initiatives.
