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Hydroelectric Generation

Harnessing Water as a Sustainable Power Source 

Hydroelectric energy, one of the oldest renewable energy sources on the planet, generates electricity when flowing water spins a wheel or turbine. As the nation's largest clean energy producer, hydropower supports our commitment to sustainability as a renewable energy source that produces zero carbon emissions, greenhouse gases or toxic byproducts.

Hydroelectric power is often associated with large-scale facilities like the Hoover Dam – a massive wall that harnesses the power of a river. However, hydroelectric facilities can also be quite low-profile. In fact, almost every state in the nation uses hydroelectricity. 

Constellation owns and operates two hydroelectric power plants along the Susquehanna River in Maryland and Pennsylvania. Together, the Conowingo Hydroelectric Generating Station and Muddy Run Pumped Storage Facility provide more than 1,600 megawatts of clean and reliable power generation, as well as much-needed load-leveling services.

Conowingo Hydroelectric Generating Station is Maryland's largest source of renewable electricity, producing more clean energy than all the other sources combined. Unlike intermittent wind and solar generation, Conowingo is able to generate power 24/7 and can respond to changes in demand, supplying extra energy to the grid within 10 minutes. In the event of a large-scale blackout, Conowingo is the first power plant called on to restart the regional electric grid. 

The Conowingo power plant produces 1.6 million megawatt hours (MWh) of electricity annually, enough to power more than 159,000 homes for a year. Additionally, the clean energy generated by the plant prevents 758,000 tons of greenhouse gas emissions (GHG), an amount equivalent to taking 150,000 cars off the road.

Learn more about Conowingo Hydroelectric Generation Station. 

Muddy Run Pumped Storage Facility is a hydroelectric power plant on the Susquehanna River that has been providing electric power to the regional transmission system since 1966. The plant’s eight units can generate 1,070 megawatts (MW) of clean electricity, an output vital to meeting the demands of the area’s regional power grid. 

To generate electricity, water in the upper reservoir at Muddy Run fuels the turbines, then flows into the Susquehanna River. At night, electricity demand decreases, so the units are reversed and used as pumps to fill the upper reservoir for use as fuel during subsequent peak-demand periods. 

Learn more about Muddy Run Pumped Storage Facility. 

At Constellation, we support local communities and causes with charitable giving and sponsorships, typically driven by our employees. In 2024, Constellation contributed $14.7 million to 4,100 organizations. Our employees donated an additional $5.3 million and contributed 116,500 volunteer hours across three dozen states. 

Learn more about Constellation's commitment to our communities. 

All of our generation facilities employ advanced emergency response plans to protect public health and safety. These comprehensive plans are carefully reviewed and approved by state governments and federal regulatory agencies. Emergency planning also involves coordination with local and municipal officials, as well as thousands of volunteers and first responders. 

To protect the safety and health of our employees, contractors, customers and communities, we’ve implemented several initiatives to promote safety both on and off the job. These include a safety behavior observation program and focused initiatives on areas of high risk. We also offer safety training, which is integrated into leadership development programs for supervisors and managers, as well as new employee orientation. Plus, the safety peer group identifies successful pilot programs and new practices that can be adopted by the entire organization.