Environmental Engineering Reference
In-Depth Information
which externalities such as ecologic problems and health impacts are taken into ac-
count.
The 20th century's energy system evolved at a time when energy (mainly fossil
fuels) was sufficiently cheap and abundant that the economic penalty for saving en-
ergy was not worth the effort, economically. Before the oil crisis, expenditures on
energy in most industries amounted to less than a few percent. After the oil crisis,
when the cost of oil quadrupled, a great effort was made to improve the efficiency
of energy use both from the “supply side,” that is, in the conversion process of
primary energy sources to electricity and on the “end-use side,” that is, the equip-
ment using the electricity or fuels, such as refrigerators, lighting apparatuses, or
automobiles.
The advantages of improved energy efficiency are reduced use of fossil fuels
and an increased security of supply, because less energy is needed to perform the
same tasks. There is also a reduction in environmental impacts.
Opportunities for reduced energy consumption exist in all steps of the energy
chain, and they are particularly important in the conversion of primary sources of
energy to energy services in residential, industrial, transportation, public, and com-
mercial sectors, as each of these sectors makes demands along the energy chain.
Reductions of more than 40% could be cost-effective and achievable in the former
Soviet Union (and other transition economies) within the next two decades as old
and inefficient technologies are replaced. In most developing countries—the cost-
effective improvement potential ranges from 30% to more than 45% owing to the
fact that most of the industrial machinery in use was imported from industrialized
countries in the past and is thus inefficient.
The implied improvements of about 2% per year could be enhanced through
structural changes in industrialized and transitional countries, shifts toward ser-
vices and less energy-intensive industrial production, and saturation effects in the
residential and transportation sectors (that is, there is a limit to the number of cars,
refrigerators, television sets, etc., that a society can absorb). Structural changes can
come from increased recycling and substitution of energy-intensive materials, im-
proved material efficiency, and intensified use of durable and investment goods.
The combined result of structural changes and efficiency improvements could ac-
celerate the annual decline in energy intensity to perhaps 2.5%. How much of this
potential will be realized depends on the effectiveness of policy frameworks and
