Glossary
Pumped-storage hydroelectricity
Pumped-storage hydroelectricity is a type of hydroelectric energy storage used in electricity generation systems. It is a grid energy storage method that works by using two water reservoirs at different elevations. This system serves both as a means of storing energy and as a method for balancing the power grid's electrical supply and demand.
In a standard operating mode, the process begins when excess grid power—or off-peak electricity—is used to pump water from a lower-located reservoir to a higher one. This can be considered as energy being stored potentiality. The water pump in this situation works as a motor, using electricity to generate mechanical force to move the water uphill. Utilizing surplus electricity in this manner is strategic, as it often occurs during periods of low demand or when there is an abundance of production from renewable sources, such as wind or solar.
Later, when the demand increases, or there is a need for more grid power, the stored water is then released from the higher reservoir. It flows back down, powering a turbine which in turn generates electricity. Here, the water pump operates as a generator, converting the stored potential energy of the water back into usable electrical energy.
This excellent method for storing excess electricity allows for a more efficient use of power plants, smoothing out their output and resolving potential issues that could arise during peak consumption hours. During times of low electricity demand, the energy effectively stored in the potential water reserve could be released within moments to satisfy a sudden increase in demand. Considering the growing shift towards renewable, but variable, energy sources, Pumped-storage hydroelectricity serves as a crucial solution for managing grid stability while maximizing the use of green energy.