Hydro-plant is a kind of comprehensive engineering service which may transfer hydroenergy to electric energy by collecting and adjusting drop and flow of natural water flow, and transmitting it to hydro turbine. Energy may be transferred by joint operation of hydro turbine and generator. Electric energy may be transmitted to electric network by transformer, switch station and transmission line.

        Hydroelectricity is clean energy. It’s reproducible and doesn’t discharge greenhouse gases. It has low operation cost (according to statistics, energy consumption of middle, small type hydro-plants is less than 1% of its electricity generation; while energy consumption of same size heat power station is as high as 35% of its electricity generation). It’s an important way of energy-saving and emission-reduction. For example, since the Three Gorges Power Station was combined to the grid, its electricity generation equals to the effect of ten five-million-ton big coal mines. And it reduces traffic volume of fifty million ton raw coals. 
Hydro-plant is divided into block power plant, power house at dam toe and diversion type hydropower station according to its layout.
Block power plant is frequently applied in the hydro-plant which has small head drop of upstream and downstream. Water is retained by its own waterwork.

　　Power house at dam toe is established when there is big head drop of upstream and downstream. And plant structure may not be able to withstand upstream water pressure. Power house is constructed at backside of water retaining building in this layout.

As for diversion type hydropower station, the water retaining building is separated from power house. Water is led into hydro turbine in power house through water diversion pipeline.

Construction of a hydro-plant involves many steps like site reconnaissance, treatment of geological basis, earthwork excavation, concrete pouring, metal structure and installation of electromechanical equipment, etc.