What type of energy does a hydroelectric dam primarily convert?

A hydroelectric dam primarily converts gravitational potential energy to electrical energy. In a hydroelectric system, water stored in a reservoir behind the dam possesses gravitational potential energy due to its elevated position. When the water is released and flows down through turbines, this potential energy is transformed into kinetic energy, which then continues to convert into mechanical energy as it turns the turbine blades.

As the turbines spin, they drive generators that convert the mechanical energy into electrical energy. Thus, the primary transformation occurs from gravitational potential energy—originating from the height of the water—to electrical energy, making the process efficient for generating power.

The other options do not accurately describe this conversion process related to hydroelectric dams.