Understanding the types of hydro power – pumped storage, impoundment, diversion, are all types of hydro power.
Impoundment or Storage Systems
Impoundment power plants are the most common and are typically large. They use a dam to store river water in a reservoir and water is released from the reservoir to flow through a turbine(s) which turns a generator to produce electricity. The water level behind the dam can be managed to either maintain a constant reservoir level or released to meet changing electrical needs.
These types of plants have enough storage capacity to off set seasonal fluctuations in water flow and usually that water storage capacity is used to provide a constant supply of electricity throughout the year.
Diversion or Run of River Systems
A Diversion system is the same as a Run of River system. It may or may not require the use of a dam. A portion of the river is channeled through a canal or penstock to a turbine. Natural water flows are not managed. These hydro systems use little, if any, stored water to provide flow to the turbine.
Although some plants have a small water storage capacity of a day or week’s worth, weather and seasonal changes cause these plants to experience significant fluctuations in power output.
]Pumped Storage System
Pumped storage systems are not conventional hydro plants. Essentially the way these systems work is that when electricity prices are cheap, water is pumped up into a storage reservoir of some type and when the price is high it is released to generate electricity.