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

5.1 Annual values
During the course of a year, the demand curve is generally lower in the summer
months than in winter.
Contrary to the daily perspective, Figure 5.1 and Figure 5.2 show, therefore, that
yearly considered PV does not correspond to the electricity demand. An increased
share of PV in electricity production, therefore, requires more storage during the
summer months. In contrast, wind energy has to be partially stored, as the electricity
supply is linked to the weather pattern. Hydropower from flowing water is
commonly used for the base load, whereas storage lakes can be used for balancing
the wind power. (Neupert, 2009; Edison, 2011)
In the Constant scenario Hydropower and PV produce more electricity in the summer
months (February until November). Geothermal energy carriers constitute only a
small amount but steadily deliver the same amount of electricity during the year.
Combined heat and power produces more electricity during the winter months, as in
the winter season heat demand is higher. The supply of wind is higher in winter
therefore the supply-curve of wind energy also shows lower values during the
summer months than in winter. Electricity demand within the Growth scenario is
much higher. To provide enough electricity, REN potentials in Austria have to be
almost completely utilized. Furthermore, to be able to cover energy demand, it will
be necessary to develop deep geothermal energy. From a today’s point of view, this
strategy is questionable, as the technology is very cost intensive. (Streicher, 2010)
43