Hydroelectricity refers to the production of electricity through the use of falling or free flowing water. Hydro power systems convert the kinetic energy in the water in a turbine which drives a generator.
Hydroelectricity is the most widely used form of renewable energy accounting for 16% of global electricity generation. China is the largest hydroelectric producer thanks to the massive Three Gorges Dam with a capacity of 20,300 MW.
The other end of the Hydro scale is known as small hydro or micro hydro. These devices can be placed in a small river and provide enough electricity to power an average home.
Although the electricity produced by hydroelectric power plants do not produce carbon emissions they can still have a significant impact on the environment due to the large reservoirs required for their operation. Areas upstream from the dam will be subject to extensive flooding. Downstream marshes and wetlands can be destroyed by the reservoir.