Many centuries ago, humans began to use the energy generated by the falling water. Initially, people used this energy in the form of machinery. In the late 19th century, people learned to convert water energy into electricity. The early hydropower stations were very small and only served the residents near the power station. With the development of transmission grids and the continuous improvement of transmission network capacity, hydropower has gradually grown toward large-scale, and has benefited from this large-scale development.

The so-called small hydropower refers to small hydropower stations with a capacity of 1.0-0.5 MW; hydropower stations with capacities less than 0.5 MW are also called rural small hydropower stations. Therefore, small hydropower also includes small-scale and micro-hydropower stations (although small-scale and micro-power stations are generally limited to supplying power to local areas). In the 1950s, China generally referred to hydropower stations below 500 kilowatts as rural hydropower stations; by the 1960s, the capacity of small hydropower stations had a limit of 3,000 kilowatts, and small power supply lines appeared in some areas; since the 1980s, with small In the implementation of rural electrification plans based on hydropower, the construction scale of small hydropower has expanded rapidly, and the definition of small hydropower stations has also expanded to 25,000 kilowatts; after the 1990s, the State Planning Commission and the Ministry of Water Resources have further clarified that hydropower stations with installed capacity below 50,000 kilowatts The preferential policies for small hydropower can be enjoyed, and some local power grids with a capacity of tens of thousands to hundreds of thousands of kVA have emerged.