Geoscience Reference
In-Depth Information
consequence of the usage of biomass converted into work was the low level of
power attainable. The power of a man using a tool is about 0.05 horsepower
(HP). That of a horse or donkey can be 10 times higher. A watermill can provide
3
5 HP, while a windmill can reach 8
10 HP. As a comparison, a steam engine
-
-
could attain 8,000
12,000 HP around 1900, while a nuclear plant can reach
2 million HP. The conquest of power meant an incredible advance in the pos-
sibility of harnessing the forces and materials of the environment. To clarify this
central point about the differences between past and modern energy systems, we
must remember that the power of an average car (80 kW) is today equal to the
power of 2,000 people and that the power of a large power station generating
electricity (800 mW) is the same as that of 20 million people. The electric power
of a medium sized nation of 40
-
60 million inhabitants, some 80,000 mW,
equals the power of 2 billion people. Today, a nuclear plant or a nuclear bomb
can concentrate millions of HP, or the work of many generations of humans and
draft animals, into a small space and a fraction of time. This concentration of
work allows humans to accomplish tasks that were barely imaginable just a few
lifetimes ago.
-
1.4 Modern Organic Fossil Economies
At the start of modern growth around 1800, on the world scale, energy consumption
was about 8,000
9,000 kcal per capita per day, that is 13 GJ per year.
10
The main
sources were those already seen, that is different kinds of biomass (food,
-
rewood
and fodder). Water and wind were the only non organic sources. In 1800,
throughout western Europe, the energy balance per head was 20 GJ per year, that is
13,000 Cal per day, excluding coal, which was then widely used only in England.
On the continent, many differences existed in the levels of energy consumption.
While in Mediterranean countries it was about 15 GJ per year (10,000 Cal per day),
in Scandinavia it was 45 (30,000 Cal per day). In pre-modern Europe, the main
energy carrier was
rewood. It represented 50 % in the south and more than 70 % in
the northern regions, followed by fodder for working animals and food for the
population.
11
In Europe, energy consumption was higher than in other agricultural civilisa-
tions, both in Asia and southern America, for two reasons:
1.
the European civilisation was the most northern agrarian civilisation and, since
temperature was a main determinant of energy consumption, wood consumption
was higher than in coeval agrarian economies;
10
On the relationship Modern Growth
—
Energy see: Ayres and Warr (
2009
).
11
See the estimates by Kander (
2002
) and Malanima (
2006
).
