The World’s Largest Batteries: Pumped Hydro

Aaron Foyer
The World’s Largest Batteries: Pumped Hydro

The intermittency of renewables needs to be managed, with energy storage being critical. Pumped hydropower facilities are a key technology providing grid-scale energy storage.

What is pumped hydropower?

Pumped hydropower is a type of energy storage system that uses the force of gravity and water to generate electricity. This system involves two reservoirs of water, one at a higher elevation and one at a lower elevation. When energy is needed, water is released from the upper reservoir and allowed to flow through turbines, which generate electricity. Then, during periods of low demand or excess supply of electricity, the water is pumped back up to the higher reservoir using electricity generated from other sources.

This process can be repeated as needed, allowing for efficient energy storage and management. Pumped hydropower is considered a flexible and reliable form of renewable energy, as it can quickly respond to changes in demand and grid stability.


  1. Energy storage: Pumped hydropower provides a reliable and efficient way to store large amounts of energy. This can help to balance the supply and demand of electricity, which is important for maintaining a stable power grid.
  2. Flexible: Pumped hydropower can respond quickly to changes in demand for electricity, which makes it a useful tool for managing fluctuations in the power grid.
  3. Renewable: Like other forms of hydropower, pumped hydropower is a renewable energy source that does not produce greenhouse gas emissions, making it a more sustainable option than fossil fuels.
  4. Long lifespan: Pumped hydropower facilities can have a lifespan of up to 50 years, making them a long-term investment.
  5. Cost-effective: Once built, pumped hydropower facilities can produce electricity at a low cost, making it an attractive option for power companies.


  1. Environmental impact: The construction of pumped hydropower facilities can have a significant environmental impact, including habitat destruction and displacement of wildlife.
  2. High upfront costs: Building pumped hydropower facilities can be expensive, which can make it difficult to justify the investment.
  3. Location-dependent: Pumped hydropower requires a specific topography with suitable elevations for reservoirs, which limits the potential locations for these facilities.
  4. Water usage: Pumped hydropower facilities require large amounts of water to operate, which can be a problem in areas with water scarcity.
  5. Limited energy storage: The amount of energy that can be stored using pumped hydropower is limited by the size of the reservoirs, which can make it challenging to meet energy demands during times of high demand.

Overall, while pumped hydropower has many advantages as an energy storage solution, it is important to consider its potential environmental impact and the high upfront costs associated with construction.


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