Pumped-storage hydroelectricity


Pumped Storage Hydropower (PSH) is one of the oldest and most efficient methods for storing electrical energy on a large scale. Due to its simplicity, reliability, and stability, it is considered one of the most important energy storage methods used in power grids around the world.

PSH systems typically consist of two water reservoirs located at different elevations. These reservoirs are connected by tunnels and pipes. During times when electricity generation exceeds consumption—such as at night or during periods of high renewable energy production from wind or solar—excess electricity is used to pump water from the lower reservoir to the upper one. In this phase, the hydro turbines operate in reverse as pumps.

When electricity demand increases—such as during peak hours—the stored water in the upper reservoir flows back down through the pipes, driving the hydro turbines. These turbines spin generators that produce electricity.

Advantages:

  • High storage capacity: PSH systems can store very large amounts of energy.

  • Long lifespan: These systems have a very long operational life and can function continuously for several decades.

  • Flexibility: They can be used to regulate the frequency and voltage of the power grid.

  • Stability: PSH systems contribute to grid stability and help prevent widespread blackouts.

  • Environmentally friendly: These systems use natural resources like water and produce no environmental pollution.

Limitations:

  • Requires suitable topography: Building a PSH plant requires two reservoirs at different elevations and appropriate land slope.

  • High initial cost: Constructing and launching a PSH plant involves significant capital investment.

  • Environmental impact: Building large reservoirs can have negative effects on the surrounding environment.

Applications:

  • Grid frequency and voltage regulation: PSH systems can quickly respond to changes in power demand and help maintain grid stability.

  • Storing renewable energy: They are ideal for storing excess energy generated from renewable sources such as wind and solar.

  • Meeting peak electricity demand: During periods of high electricity demand, PSH systems serve as a fast and reliable power supply.