Environmental Engineering Reference
In-Depth Information
Regions
Range of estimates
South Asia
39-1,339 EJ
Centrally planned Asia
116-4,135 EJ
Pacific OECD
73-2,263 EJ
Total
1,575-49,837 EJ
4.5 Solar Photovoltaics
The New Age of the Sun?
Most animistic and polytheistic cultures - from the Inuit to the Aborigines, from ancient
Greeks to modern Hindus - have worshipped the sun. Though we have only recently
grasped the scientific composition of light, our appreciation of the sun's centrality to all life
is seemingly as old as humanity. The sun is the source of all life on Earth and all energy
in our solar system. All plants rely on sunlight to synthesize food, and all animals rely -
directly or indirectly - on those plants. Fossil fuels are ancient plant and animal biomass,
windenergyrelies onair movements between hotandcold zones, andhydropowerdepends
on evaporation to raise water from oceans to mountains. Even uranium, the fuel for nuclear
power plants, is related to the sun, having been formed in the same great explosion that
gave birth to most of the elements of our solar system.
NotonlyisthesuntheoriginofallenergyonEarth;itisalso,initself,themostabundant
of energy resources. The amount of sunlight energy that strikes the Earth in a single hour
that the future of human civilisation will depend on our ability to harness this resource
since fossil fuels must, sooner or later, run out. So far we have developed two principal
approaches to solar energy - collecting heat and generating electricity. Since electricity is
by far the more versatile of these two energy forms (in terms of transport and conversion),
it is also where the greatest hope is invested.
The first step towards converting sunlight into electricity was taken in 1839, when the
French physicist Edmond Becquerel observed an increase in electrical current when the
