This type of power station uses hydro energy from large rivers. The difference between headwater and tailwater levels is marginal in comparison to the high-pressure storage power plant but an increase in headwater levels by a few meters in lowland areas can lead to the creation of vast reservoirs. This is not necessarily a drawback. There are well-known examples of reservoirs on the Central Plateau in Switzerland, whose banks have become extensive nature reserves or recreational areas (examples: Klingnau, Eglisau, Bremgarten-Zufikon, etc.).

The low-pressure run-of-river power station must operate in accordance with the water regime of the river. Switching off the turbines would lead to an unacceptable rise in headwater levels. This is avoided by opening the control gates, although this results in the loss of valuable energy. The river-flow power station is therefore the “classical” supplier of base-load energy. The most common type of turbine for low pressure power stations is the vertical Kaplan turbine and more recently the pipe turbine.