As a part of the strive for renewable energy production, Portugal is constructing a new hydro plant that in effect will work as a giant battery.
By utilizing renewable energy from wind, sun, wave and hydro power to pump water up to a giant reservoir during periods of low electricity demand – such as during night time or on weekends – the hydro plant’s water reserve is “reloaded” with water that later can be used in the usual way to produce hydro electricity when needed.
In this way the hydro plant works as a giant battery, storing energy for later use. The technique is not entirely new – similar setups already exist – but for Portugal the new construction will bring the country further on its way to get 80 percent of their energy needs from renewable sources.
Source: ARD Tagesschau