Environmental Engineering Reference
In-Depth Information
After the Second World War the demand for energy soared, and fossil energy
sources were able to increase their share substantially. In 2007 fossil energies
covered around 80% of the world's primary energy needs (Figure 1.5). Hydropower
and nuclear energy had a share of around 6% and 5%, respectively, and biomass
close to 10%. The other renewable energies amounted to less than 1% with geo-
thermal energy - use of the earth's heat - having the largest share. At the beginning
of the 21st century renewable energies such as wind power and solar energy, which
until then had been used relatively little, started to record double-digit growth rates.
It is expected that their share of worldwide energy supply will increase considerably
in coming years.
550
other renewables
biomass
hydro power
nuclear power
coal
natural gas
crude oil
500
450
400
350
300
250
200
150
100
50
0
Figure 1.5
Development of primary energy demand worldwide since 1965.
1.2 Energy Needs - Who Needs What, Where and
How Much?
Demand for energy is distributed unevenly across the world. Six countries, namely
the USA, China, Russia, India, Japan and Germany, use more than half the available
energy.
The USA alone needs one-fi fth of the energy used in the world, even though only
one-twentieth of the worldwide population lives there. If every citizen of India were
to use as much energy as each American, global demand for energy would rise by
about 70%. If all the people on earth developed the same hunger for energy as the
Americans, demand would increase fourfold.
