Itaipu (or comparable impoundages such as Three Gorges) provide both capacity, indicated as installed GWe of generating capability, a measure of power, and storage, indicated as GWH of energy generation. These are equivalent to the capabilities of an automobile's engine (power) and fuel tank (storage).
Hydroelectric projects also virtually always provide additional services such as flood control, irrigation water, recreation, and waterways management (ensuring water flows, etc.), which also account for design elements including scale, etc.
Pumped hydro should provide a sufficient level of both capacity and storage, though in general the storage requirements are far smaller than traditional hydroelectric dams aimed at generation. There are quite small pumped hydro facilities, the compensation being that water levels can rise or fall considerably, often many metres in a single day's storage/generation cycle.
Gravity is in general a weak force, but water is relatively massive, largely non-toxic, and can be utilised through large-scale pump-generator units (~800 MW per generator IIRC), which is a scale few other options can match. Again, on balance, pumped hydro is a good solution, there's just not enough of it to go around.
> What does the Itaipu Dam's installed power have to do with stored energy?
Nothing. Was there something to suggest otherwise? I listed two weak points for hydro: Terrible energy density, massive land use.
My first reference supported the first point and my second reference addressed the second point. Land use: 1,350 square kilometres were flooded. The installed power was to give context of how big the plant is.
Again: the size is incidental to that specific dam. Pumped hydro facilities can be vastly smaller.
Ffestiniog Power Station in the UK is on the order of 1 hectare (1/100 km^2) in area (based on 170,000 m^3 storage and a 34m dam height). It's a modest and early pumped-hydro facility.
Bath County Pumped Storage in the US has an upper reservoir of 107 and a lower of 226 hectares respectively, or 1 km^2 and 2 km^2, roughly. It is the largest in the US.
There is no reason for a purely pumped-hydro facility to be anywhere remotely near the size of Itaipu. Which is not in fact a pumped hydroelectric storage facility, but a hydroelectric generating station with no pumped-hydro storage capabilities or functions.
Hydroelectric projects also virtually always provide additional services such as flood control, irrigation water, recreation, and waterways management (ensuring water flows, etc.), which also account for design elements including scale, etc.
Pumped hydro should provide a sufficient level of both capacity and storage, though in general the storage requirements are far smaller than traditional hydroelectric dams aimed at generation. There are quite small pumped hydro facilities, the compensation being that water levels can rise or fall considerably, often many metres in a single day's storage/generation cycle.
Gravity is in general a weak force, but water is relatively massive, largely non-toxic, and can be utilised through large-scale pump-generator units (~800 MW per generator IIRC), which is a scale few other options can match. Again, on balance, pumped hydro is a good solution, there's just not enough of it to go around.