Environmental Engineering Reference
In-Depth Information
•
substantial reduction in biodiversity, and
•
more severe bushfire seasons.
It is possible that there will be unexpected catastrophes over the next few
decades such as loss of the Gulf Stream, due to changes in the circulation of
the Atlantic Ocean, and destruction of the Amazon rainforest (see Chapter 7
,
for more details). Other problems include oil spills, oil-related warfare (for
example, the Gulf wars) and pollution from acid rain, particulates and pho-
tochemical smog.
Nuclear energy from fission has severe problems relating to waste dis-
posal, reactor accidents, nuclear weapons proliferation and nuclear terror-
ism. A country that possesses a nuclear energy industry has the raw
materials, the technology and the trained people required for the production
of nuclear weapons. Several countries have acquired nuclear weapons tech-
nology via the route of civilian nuclear energy and so such an energy source
carries with it negative implications for nuclear weapons proliferation.
Nuclear fusion is still many decades away from commercial utilisation.
Geothermal energy is heat energy that comes from the decay of radioac-
tive elements within the Earth. Heat associated with volcanic regions can be
used to generate steam for district heating or to drive steam turbines to
produce electricity. Another form of geothermal energy is 'hot dry rocks',
which refers to hot masses of slightly radioactive rock buried several kilome-
tres below the surface of the Earth. Cold water forced down to this hot rock
becomes steam that can be extracted from boreholes nearby. Geothermal
energy is restricted to particular geographical locations. While it is sustaina-
ble in the sense that it can be harvested with limited environmental damage,
the heat stored in a particular place can certainly be depleted. An Australian
company, Geodynamics, is attempting to commercialise this energy source
(Geodynamics 2003).
Tidal energy (energy generated from the flow of water during incoming
and outgoing tides) can be collected using what amounts to a coastal hydro-
electric system. It is sustainable in the sense that it will not run out. However,
the coastline is a scarce resource and the collection of large amounts of tidal
energy will have a major environmental impact due to flooding of ecosys-
tems by such schemes.
Solar energy, by contrast, is available on a massive scale. Solar energy can
eliminate the need for fossil and nuclear fuels over the next 50 years. The col-
lection and conversion methods usually (though not always) entail few envi-
