requirements for a power-supply
with renewable energies
necessary capacity requirements of storage power plants in order to
equalize the difference between a weather dependent production and the
requested power, can be calculated, for Europe, from available data of
wind speed and solar radiation. In the form of “load divergence” and
“storage emptying curves” suitable calculation methods were developed
for this purpose. The good availability of data in Germany makes it
possible to compare the actual wind and solar power feeds with the
calculated values. Thereby the calculations could be validated.
country produces its own average consumption plus a certain reserve from
wind- and solar power stations, then the storage requirements to
equalize the difference between power production and consumption would
require a storage load from a few days up to some months of the average
consumption. This huge difference is caused by several influences. On
one hand by the continental distribution and cross linking of renewable
power production, which enables considerable equalizing effects between
temporary overproduction and deficits, because high- and low-pressure
areas move across the continent and provide different regions of
weather. Furthermore strong winds occur in Europe mainly during winter
time. An optimized combination of power production using wind- and solar
energy on the other hand reduces the need to balance dramatically in
comparison to a mono structure using only wind- or only solar power
Considerable influence also has the capacity factor of wind power
stations. It tells the amount of average power output compared to the
rated power. Wind power stations in Germany in the year 2010 have a
capacity factor of about 20%. This value proves unfortunate to the intended
increase of wind power to the total power supply. The equalizing and
storage needs could be drastically reduced by using wind power stations
with an efficiency of 50% for example.
strong lever to reduce the equalization needs is the power production
reserve. A bigger reserve will reduce the time where storage power is
required and will accelerate the refilling of an emptied storage plant.
tuning of all parameters allows a secure power supply what will meet the
demands with a storage capacity of only a few days. The storage capacity
needed would be much more than available in the year 2010.
Ringwallspeicher as a new type of
pumped-storage power plants are introduced. They could be built in all
countries and could close the gap of missing storage capacity.
power supply, only using wind-, solar- and storage power plants in
Europe is therefore a real option.