The photo is sourced lockbox.lockton.com
A key role in the development of the industry is played by China, which provided 67% (7.1 GW) of the PSPPs put into operation worldwide in 2022 and 74% (7.9 GW) of those put into operation in 2023. Other important points of growth for the industry are India and Egypt, where a total of 3.9 GW of PSPPs were brought into operation in 2022–2023.
As a rule, PSPPs are equipped with two reservoirs with an elevation difference: in the night and daytime hours, water is pumped from the lower reservoir into the upper one using cheaper electricity from the common grid, while in the morning and evening hours, it gets discharged back into the lower reservoir, setting off power generator turbines.
The utilisation rate of PSPPs depends not only on the time of day but also, to a large extent, on the season: for instance, the utilisation rate of PSPPs in the United States stands at 7–9% in the winter months for energy storage purposes, reaching 14–16% in the summer, according to the U.S. Energy Information Administration (EIA). This correlation is caused by an increased load on the grid due to growing demand for air conditioning, as well as a seasonal reduction in precipitation, which makes owners pump water from the lower reservoir to the upper one more often to ensure the very possibility of electricity generation.
Another advantage of PSPPs is the ability to utilise excess electricity from wind and solar generators, especially during hours of low demand. In view of the rapid development of wind and solar generation, this largely explains the growing popularity of PSPPs. While PSPPs accounted for just 15% of the capacity of hydroelectric power plants operating around the world by May 2023 (166.1 GW out of 1,131 GW), their share was already at 52% (101 GW out of 193.8 GW) in the segment of facilities under construction. This is why the current record for the number of new PSPPs being put into operation will most likely be bested in the coming years.
