Conowingo Hydroelectric Plant is a dam on the lower Susquehana River in north eastern Maryland. The Susquehana River flows through Pensylvania and Maryland, emptying in the Chesapeake Bay.

The Conowingo Project began in 1926, and was the lingle largest generating station ever bilt in one step and used the largest turbines ever produced to generate electricity. The output of the seven turbines was second only to Niagra Falls.

The original output of the hydroelectric plant was 252 Megawatts, but in 1964, it was upgraded to 512 Megawatts. The plant contains the original seven turbines, each producing 36 Megawatts apiece, and four larger units rated at 65 Megawatts each. The Conowingo Hydroelectric Plant provides pwer for over 300,000 homes.

In 1972, "fish lifts" were added to the plant to allow fish to savely navagate the Susquehana River. In 1991 another lift was installed, and presently the lifts can accomidate the transfer of 750,000 fish in one season. This is the largest lift system is the largest in the United States.

The Conowingo Hydroelectric Plant utilizes a 89-foot drop in the Susquehana River to produce electricity. The two intakes have a concrete curtain and screen to prevent trash, ice, and debris from entering the dam. The water then enters the penstock and travels to the wicket gates. These gates control the flow of water into the turbines. The water then exits through the flood gates. The turbines turn generators which create energy by converting mechanical energy to electrical energy. The generators produce 13,800 volts of electricity which is stepped up, using transformeres, to 220,000 volts before being transmitted through power lines to Philadelphia.

Facts and Figures

  Length                                4,648 feet
  Height above riverbed                 104 feet at roadbed
  Width at base                         85 feet at spillways
  Resevoir area (Conowingo Pond)        14 square miles
  Water flow at full generation         687,000 gallons per second
  Plant capacity                        512,000 Kilowatts
  Generation voltage                    13,800 volts
  Transmission voltage at power lines   220,000 volts