Environmental Engineering Reference
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attributable to massive consumption by billions of people in poorer countries (IEA 2012a
and IEA website).
Thoughglobalprimaryproductionhasdoubledsincetheearly1970s,theenergymixhas
not changed much. Only nuclear power, with its sixfold growth, has significantly increased
its share (see Figure 7.1 ). Despite the introduction of nuclear energy and various new
renewables, fossil fuels still account for 85 per cent of global primary energy, down just a
single percentage point from 1973.
Figure 7.1. Since the first oil crisis, total primary energy supply has doubled, yet the
energy mix has not changed considerably, and fossil fuels still dominate. New renewables
(represented in the diagram above as 'Others', which include wind, solar, geothermal and
ocean energy, and exclude biomass and hydropower) still account for less than 1 per cent
of primary energy supply. Sources: IEA ( 2012a ) and IEA website.
Table 7.1. Changes in energy production compared with population increase
during the last three centuries
Year
1700
1800
1900
2000
Fossil fuels and electricity (EJ/year) 0
1.5
22.5 390
Biomass (EJ/year)
10
12
21
42
Population (billion)
0.63 0.98 1.65 6.09
Source: Smil ( 2008 ).
Figure 7.2. Electricity generation has tripled since 1973. Diversification is more evident
in this sector than in primary energy supply. A drastic reduction in the use of oil for power
generation has facilitated the emergence of nuclear, natural gas and new renewables. Coal
remains the most important fuel for power generation. Sources: IEA ( 2012a ) and IEA
website.
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