Hydropower is a form of energy that is generated by the constant movement of water. Hydropower is a renewable source of energy, meaning it can be used again and renewed at any time. Hydroelectric power was the first and simplest electricity generator. Moving water sources used for hydropower can include rivers, rain and snow. According to many studies, hydroelectricity produces 10 percent of the world’s energy. One popular way we use hydropower is by hydroelectric power plants. A hydroelectric power plant is a facility for generating hydroelectricity. Dams are usually installed and seen over rivers. A dam is a type of barrier that is mainly created to hold back water, to raise up its level and to produce electricity. When the water in the river flows through the dam, it will turn blades on a turbine. This will then convert the energy from the falling water into electricity. The electricity will then travel through a long distance power lines to transfer to a factory. As the water is transferred into electricity, the water in the river is then replaced by rain. Hydroelectric power plants produce very little pollution. Because of this, people often think of Hydroelectricity as a fresh and productive source of energy. However, this is not the case at all with hydroelectricity. Hydroelectricity has a huge impact on the environment. Dams can eventually start to change the flow of the river by continuously converting water into electricity to then raise the sea level behind it. This can have an effect on the river erosion that there already is. This will damage river ecosystems. This can also flood monumental amounts of land. Another type of hydroelectric power plant that can store energy is the Pumped storage plant. A pumped storage plant is a hydroelectric energy storage that is mainly utilized by different types of electrical power sources for load balancing. Load balancing is a very popular and important technique used by electrical power stations to keep electrical power. Pumped storage holds energy in the form of gravitational potential energy of water pumped from a lower elevation of water to a larger one. Hydroelectricity improves the air we breathe due to the lack of pollutants power plants release. Hydroelectricity is also very cheap to use.