Water sits in a lake behind a dam. Then the water rushes from the lake through the dam and down to a river. Inside the dam, the rushing water flows through a turbine. The energy from the falling water spins the turbine. The turbine then turns a generator and the generators produce electricity. The electricity flows through a power station and then onto high voltage power lines to another power station inside a city. From there, the electricity flows through more power lines and into houses.