Energy - Environmental Science - page 287

Oil and natural gas

Floating oil drilling platform

Oil storage

Coal

Contour
strip mining

Geothermal energy

Oil drilling
platform
on legs

Hot water storage

Geothermal
power plant

Oil well

Pipeline

Gas well

Valves

Mined coal

Area strip
mining

Pump

Pipeline

Drilling
tower

Coal seam

Water penetrates
down through
the rock

Figure 13-2 Natural capital: important nonrenewable energy resources that
can be removed from the earth's crust are coal, oil, natural gas, and some
forms of geothermal energy. Nonrenewable uranium ore is also extracted from
the earth's crust and then processed to increase its concentration of uranium-
235, which can serve as a fuel in nuclear reactors to produce electricity.

Nuclear power
6%

Nuclear power
8%

Hydropower, geothermal,
solar, wind
7%

Hydropower
geothermal,
solar, wind
3%

,

Natural
gas
23%

Natural
gas
21%

Biomass
11%

Coal
23%

Coal
22%

Biomass
4%

Oil
33%

Oil
39%

World United States

Figure 13-3 Natural capital: commercial energy use by source for the world (left) and the United States (right)
in 2003. Commercial energy amounts to only 1% of the energy used in the world; the other 99% is direct solar
energy received from the sun and is not sold in the marketplace. (Data from U.S. Department of Energy, British
Petroleum, Worldwatch Institute, and International Energy Agency)