Fossil Fuels and Alternative Energy Sources
As you learned in the section on nonrenewable resources, fossil fuels, such as petroleum,
coal, and natural gas, exist in fixed amounts, take millions of years to form naturally, and
cannot be replaced as fast as they are consumed. They range from very volatile (explosive)
materials like methane, to liquid petroleum to nonvolatile materials like coal.
It was estimated in 2005 that 86% of primary energy production in the world came from
burning fossil fuels. Concern about fossil fuels is one of the causes of regional and global
conflicts, and the production and use of fossil fuels raise concerns about the environment.
A global movement toward the generation of alternative energy sources, which are renew-
able, is therefore under way to help meet increased energy needs. Some of these, like solar
radiation, wind energy, and hydropower, were mentioned briefly in the section on renewable
resources. Let’s discuss these and others now in more detail.
- Solar power(Figure25.18) involves using solar cells to convert sunlight into elec-
tricity. When sunlight hits solar thermal panels, it is converted to heat water or air.
It can also be used to heat water (producing steam) via a parabolic mirror, or it can
be used for passive solar heating of a building simply by passing through windows.
Figure 25.18: An example of solar power, using solar cells to convert sunlight into electricity.
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- Wind power,the conversion of wind energy into forms such as electricity via wind
turbines, is only used for less than 1% of the world’s energy needs. However, growth
in harvesting wind energy is rapid, with recent annual increases of more than 30%.