Environmental Engineering Reference
In-Depth Information
Around 800 millimetres or 0.8 cubic metres of rain fall per square metre in Germany.
The annual rainfall for all of Germany adds up to 286 billion cubic metres. The sun
evaporates this water before it reaches earth in the form of rain. One cubic metre
of water requires 627 kilowatt hours to evaporate. This means the annual rainfall
contains around 170 trillion kilowatt hours of energy.
About 2% of solar energy is converted through the movement of the wind. In
Germany this amounts to around 8 trillion kilowatt hours. Sun, wind and water
together produce abound 567 trillion kilowatt hours of energy in Germany each
year. Geothermal and ocean energy are not even included in these fi gures. If this
quantity of energy were to drop even a few percentage points, the result would be
drought and arctic winters (Figure 1.8 ).
anyway
hydro
179 PWh
anyway wind
8 PWh
nuclear
0.5 PWh
fossil fuels
3.3 PWh
anyway sun
380 PWh
Figure 1.8
Total energy resources in Germany
taking into account 'anyway' energy; that is,
natural renewable forms of energy.
The statistics of 2007 listed Germany's primary energy requirements as being
around 14 000 petajoules. This converts to close to 4 trillion kilowatt hours. Of
course, the statistic includes solar energy, hydropower and wind energy. The propor-
tion of all renewable energies combined in the requirement for primary energy totals
0.183 trillion kilowatt hours. This is the amount that technical installations convert
into renewable energy. The natural forms of renewable energy that exist anyway
are totally omitted from this statistic. This explains the small obvious statistical
discrepancy for the previous calculation of 567 trillion kilowatt hours for renewable
energy resources. The difference between this and conventional statistics is clarifi ed
in Figure 1.8, where the natural renewable forms of energy that previously were not
recorded in the statistics are referred to as 'anyway' energy - in other words, energy
that exists anyway.
Anyone who thinks that these calculations amount to statistical hairsplitting is
wrong. As the facts about climate change have now become public knowledge, there
is a general interest in replacing fossil fuels with renewable energies as quickly as
possible. But many people are under the impression that this is diffi cult to implement
and almost impossible to accomplish within a reasonable period of time. The claim
that solar energy only constitutes an insignifi cant share of energy resources is
repeated like a prayer wheel. If the claim were true, this scepticism would be justi-
fi ed. In fact, it is fossil and nuclear energies that make up 0.6% of the energy
resources in Germany. And no one could seriously doubt that 0.6% is replaceable
in the foreseeable future.
