example of a resource in unlimited supply, as well ashydropower, which is renewed by the
Earth’s hydrologic cycle.
Figure 25.14: Solar radiation and wind energy are considered renewable resources because
availability of both far exceeds our rate of consumption. 89,000 TW (terawatts) represents
the amount of sunlight that falls on the Earth’s surface, 370 TW depicts wind energy avail-
able, and 15 TW was the global rate of energy consumption in 2004. ( 21 )
Figure 25.15: Wind power, another renewable resource, shown here in a modern wind energy
plant. ( 22 )
Based on what you learned in the last two lessons, would you say air and water are renewable
resources? They may appear to be, but your knowledge about air and water pollution would
tell you that clean air and water are not always so accessible. As we think about other