The relevance of energy storages for an autarky of electricity supply ...

4.4 Pumped Hydroelectric Storage
In general, hydropower is most useful to cover the base load and to store excess
electricity (e.g. from wind energy). It is used in load management and when there is
no need for very quick response. Pumped Hydroelectric Storage is the most common
technology to store electricity. (Neupert, 2009; Alamri, 2009) The current potential
for Pumped Hydroelectric Storage is 7.000 MW in Austria. Due to a study of Booz &
Company, it can be increased by around 60 % or 4.300 MW until the year 2020. 4
4.4.1 Technical description
Pumped Hydroelectric Storage can either be natural or artificially constructed. It can
include underground caverns, old mine shafts, volumes formerly occupied by oil or
newly excavated volume. Electricity is produced when water runs from the upper
basin to the lower through turbines. At times, when there is over-supply usually
during night, electricity prices are lower and water can be pumped up to the storage
area at the higher level, recharging the system. In some cases so-called two-way
turbines are used for such installations. (Rummich, 2009; Edison, 2011) A schematic
illustration can be seen in Figure 4.1.
Figure 4.1: Schematic illustration of a pumped-hydro system (Quaschnig, 2009)
4 http://relevant.at/wirtschaft/energie/154528/pumpspeicher-kws-oesterreich-gruene-batterie.story,
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