  The main advantage of wind and solar power plants is the power production
free of CO2. Their main disadvantage is the volatility of the generated power.
According to the estimates of H.-W. Sinn[1], suppressing this volatility
requires pumped-storage plants with a huge capacity, several orders of
magnitude larger than the present available capacity in Germany[2]. Sinn
concluded that wind-solar power can be used only together with conventional
power plants as backups. However, based on German power data[3] of 2019 we show
that the required storage capacity can significantly be reduced, provided i) a
surplus of wind-solar power plants is supplied, ii) smart meters are installed,
iii) partly a different kind of wind turbines and solar panels are used in
Germany. Our calculations suggest that all the electric energy, presently
produced in Germany, can be obtained from wind-solar power alone. And our
results let us predict that wind-solar power can be used to produce in addition
the energy for transportation, warm water, space heating and in part for
process heating, meaning an increase of the present electric energy production
by a factor of about 5[1]. Of course, to put such a prediction on firm ground
the present calculations have to be confirmed for a period of many years. And
it should be kept in mind, that in any case a huge number of wind turbines and
solar panels is required.
