Environmental Engineering Reference
In-Depth Information
Geothermal and
other sources
Hydroelectric 7.5
0.7
Nuclear-electric 6.3
39
Petroleum
21.5
Natural gas
25 Coal
Figure 2.2
Proportions (%) of world's energy consumption supplied by primary energy sources, 1997.
(
Source:
Same as in Figure 2.1.)
250
History
Projections
200
Oil
Natural gas
150
Coal
100
Renewables
50
Nuclear
0
1970
1980
1990
2000
2010
2020
Figure 2.3
The trend of the growth of energy sources from 1970 to 1997 and the prediction to 2020.
(
Source:
Same as in Figure 2.1.)
presumably with increase of the use of solar, wind, and biomass energy. The consumption of all
fossil fuels will also increase in the next decades, with the rise of natural gas use exceeding that of
coal by the year 2020.
Taken as a linear growth rate over the 10 years 1987-1997, the worldwide energy consumption
was increasing at approximately 1.55% per year. Coal consumption grew by 0.8%/y on the av-
erage, natural gas 2.45%/y, petroleum 1.1%/y, nuclear-electric 2.2%/y, hydroelectric 2.1%/y, and
geothermal and other energy sources 13%/y. However, as mentioned above, the latter constitute
only a small fraction of the current energy consumption. In the United States, energy consumption
increased 1.7%/y on the average over the 10 years. China's energy consumption grew 5.3%/y on
the average, whereas India's energy use increased about 6.6%/y. Most of the growth is due to
increased fossil fuel consumption.
In 1996, the total energy consumption in the United States was close to 90 Q. The distri-
bution of the U.S. energy consumption by energy source is presented in Figure 2.4. Petroleum
contributed 39.7%, natural gas 25.1%, coal 22.8%, nuclear-electricity 8%, hydroelectricity 4%,
