Effective energy
Only about 1/3 of the primary energy is effective energy which is actually used
by customers in form of heating, light, processing, motion, and communication.
The other 2/3 is lost when transforming the primary energy sources into effective
energy. As an example, in Germany only 1400 TWh a − 1 of energy is effectively used.
About 570 TW a − 1 of this energy is actually electricity. To cover these quantities, the
electricity is produced mainly by using fossil energy sources (60%) like hard coal,
petroleum, or natural gas (Figure 1.4 ); 30% is derived from nuclear power stations,
while the amount of electricity from renewable energy sources is only about 7.25%
to date.