Correct answer: Turbines
Hydroelectric and coal power plants both produce the electricity in a similar way. Water is heated to turn it into steam, which runs the turbine. As the turbine spins, it rotates the metal shaft which is connected to the generator, which is actually a motor that produces electricity.
After the stem passes the turbine, the steam is condensed into a condenser, the waste heat is used to raised stem that improves the overall efficiency of the plant.
