Hydroelectric power is a means of providing electricity from the forces of moving water, and is the leading renewable energy source in the world. Hydropower plants account for about 24% of the world's power supply.  Hydroelectric power is seen both in large dams and in "small hydro" projects that are much smaller in scale, and might serve just one community. Larger hydroplants use dams to hold back water, creating a large reservoir of water, which is potential energy. The water becomes kinetic energy when a gate is opened, allowing the water to flow down and turn the blades of a turbine, creating energy.