Geoscience Reference
In-Depth Information
180
1000
y = 20,65e
0,01x
R
2
= 0,97
150
120
100
90
60
10
30
0
1
Fig. 1.4 Per capita energy consumption in western Europe 1800
2007 (GJ) (on the right log
vertical axis, trend and the equation of the trend). Source Kander et al. (
2013
)
-
was 33 times (Table
1.4
). We see that modern or commercial sources overcame
traditional sources, or the phytomass, around 1900, or the epoch of the second
industrial revolution.
1.4.3 The Process of Substitution
In organic vegetable economies any discovery of a new source was an addition to
the balance of energy and not a substitution. With fossil sources it was different.
Fossil sources replaced a large part of the traditional carriers, which lost their
importance in relative and sometimes in absolute terms. While food consumption
rose in aggregate and per capita terms, the power of working animals diminished
and, in developed economies, totally disappeared. Firewood continued to represent
an important share of energy consumption only in relatively backward areas. On the
world scale, traditional sources of energy diminished from 98 % in 1800 to 50 in
1900 and only 14 in 2000
2010. In Europe the decline was still higher. England was
the only important consumer of coal at the beginning of the 19th century. Traditional
sources then represented the greater majority throughout the continent, that is almost
90 % of the overall consumption (when England is excluded). Their share decreased
to 25 % in 1900 and was only 5 % in 2000 (always excluding England).
For several millennia changes in the energy system had been very slow. From
1800 transitions and substitutions began to dominate the picture. If we look at the
fuels utilized in Europe from 1800 until 2000, we see that, in terms of Calories,
-
rewood still dominated in 1800, while coal represented about 30 %. Wood con-
sumption was, in relative terms, already relatively modest in 1900, while coal
equalled about 80 %. Oil began to be used during the last decades of the 19th
century and only in the 1960s exceeded coal. Natural gas spread from the 1970s on
a large scale and only in the 1990s did it overtake coal; although its share was less
than half that of oil. While coal dominated for a long period in the last half century,
