Environmental Engineering Reference
In-Depth Information
11
CHAPTER
Concluding Remarks
11.1
ENERGY RESOURCES
At the beginning of this topic we reviewed the energy resources available to mankind and the
uses of these resources in the various countries of the world; in subsequent chapters we outlined
the environmental effects associated with energy use. The supply and use of energy has other
important consequences: economic and political. Energy is a necessary and significant factor of
national economies; energy expenditures amount to 5-10% of the GDP in industrialized nations.
The availability of adequate energy to enterprises and individuals is a national goal and is thereby
affected by governmental policies.
Among fossil energy resources, coal appears to be available in abundance for at least two
to three centuries, while the fluid fossil fuels, petroleum and natural gas, may last for less than a
century. The availability of fluid fuel resources can be extended by manufacturing them from coal
by coal gasification and liquefaction. (The manufactured fluid fuels are called synfuels.) Fluid fuels
can also be obtained from unconventional resources, such as oil shale, tar sands, geopressurized
methane, coal seam methane, and methane hydrates lying on the bottom of the oceans and under the
icecaps. The manufacture of synfuels and the exploitation of unconventional fossil fuel resources
will be more expensive than the exploitation of proven reserves, and the manufacturing and recovery
processes will entail more severe environmental effects than those associated with exploitation of
conventional reserves.
Electricity is an essential energy component of modern industrialized societies; its use is
increasing worldwide. Electricity is a secondary form of energy; it has to be generated from primary
energy sources. Presently about two-thirds of the world's electricity is generated from fossil fuels
while the other third comes from hydroenergy and nuclear energy, with very minor contributions
from wind, biomass, and geothermal sources.
In 1997, about 17% of the world's electricity and 6.3% of its energy was supplied by nuclear
power plants. The global resources of the raw material for nuclear power plants—uranium and
thorium—would last centuries, at current usage rates. These resources can be extended even further
in the so-called breeder reactors, where artificial fissile isotopes can be generated from natural
uranium and thorium. Nuclear power plants are much more complex and expensive to build and
operate than fossil-fueled plants. Also, the real and perceived hazards of nuclear power plants,
including the risks of the entire nuclear fuel cycle, from mining to refining to radioactive waste
disposal, militates against building new nuclear power plants in many countries. However, with
depleting fossil fuel resources and the associated environmental risks of fossil-fueled power plants,
notably global warming due to CO
2
emissions, it is likely that in the future nuclear power will
again assume a substantial share of the world's electricity generation.
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