Environmental Engineering Reference
In-Depth Information
Fig. 1.1 World primary
energy consumptions 2007
(total = 11099 Mtoe) [
3
]
Hydroelectricity
Nuclear
6,4%
5,6%
Oil
36%
Coal
28%
24%
Natural gas
mass of people some limitations until then ignored: geopolitical and financial
involvements, depletion of available reserves, environmental impact. The first
concern, with its implications on oil price jumps, is not a topic of this topic and can
be examined closely starting from other publications [
4
-
8
], while the environ-
mental impact related to the use of oil-derived hydrocarbons as current transpor-
tation fuels will be addressed in next paragraphs. Due to the crucial dependence of
transportation means on this resource, some considerations about the controversial
problem of future oil availability are presented here.
The limited availability of petroleum is not questionable, because of its fossil
nature, then exhaustible and not renewable (millions of years have been necessary
to form the oil today extracted, a period of time not comparable to that of its
utilization, which is restricted in few decades). The critical issues regard the
amount actually still present in the ground and the real possibility and convenience
of extracting it. The question of the existing reserves is not easy to be cleared,
because of a number of reasons: many oil producers may declare major reserves
than those really available in order to obtain financial or political credits, the
search of new oil-fields requires new prospecting technologies still under devel-
opment, any new technology which could favor an increase of production from
either existing or new oil-well imposes significant investments (today about 40%
of each well is exploited, and higher percentage would possible by more costly
technologies). However, a famous model, proposed by the geologist Hubbert on
1949 [
9
], can be used as basis for estimations about the petroleum left for the
future. The Hubbert theory analyzed the ultimate recoverable reserves of crude oil
in USA, and was based on the historical annual production data cumulated over the
total period of extraction, and on extrapolation of these data to the ultimate
extractable amount of petroleum. Applying this model, the oil production curve
results ''bell shaped'' and approximately symmetric, with an early period of
exponential growth of the production rate, followed by a maximum value and
successive diminution as the integrated production reaches the total amount of the
resource. The application of the Hubbert model predicted in the mid 1950s that oil
production of USA would reach a peak between 1965 and 1970 [
10
]. This pre-
diction turned out to be very close to the mark, in fact oil production of USA
reached a maximum in 1971, and after then they are importing petroleum with a
production reduced to about half than that of 1960. The peak oil theory has been
