"pumped hydro is currently the largest source of electrical energy storage with more than 95% of the world’s electricity storage power (GW) capacity and 99% of the storage energy " is that correct?
The first part is correct. Pumped hydro is the dominant form of electrical energy storage by a wide margin. Here are some sources that confirm this:
Department of Energy:
https://www.energy.gov/eere/water/pu...age-hydropower says pumped storage hydropower is "the most dominant form of energy storage on the electric grid today".
International Hydropower Association:
https://www.hydropower.org/factsheets/pumped-storage states pumped hydro accounts for "over 94 per cent of installed global energy storage capacity".
The second part about 99% of the storage energy is likely an exaggeration.
While pumped hydro holds a significant share, it's not quite that high. It's difficult to get a definitive number on total storage energy because unlike capacity (the potential amount that can be stored), storage energy depends on how the system is used. However, most sources agree it's well below 99%.
Here's a breakdown:
Pumped hydro is very efficient at storing and releasing energy, but some energy is lost in the process.
The amount of energy stored depends on how much energy is used to pump the water up in the first place.
So,
pumped hydro is undeniably the leading energy storage solution, but 95% of capacity is a more accurate figure than 99% of storage energy.