Figure 5.2: Like other fossil fuels, this piece of anthracite coal is a nonrenewable energy
resource. ( 10 )
years to form, we are using them up in a matter of decades and will soon run out. Fossil
fuels are nonrenewable resources. The burning of fossil fuels also releases large amounts of
the greenhouse gas carbon dioxide.
Types of Renewable Resources
Renewable energy resources include solar, water, wind, biomass, and geothermal power.
These resources can usually be replaced at the same rate that we use them. Scientists know
that the sun will continue to shine for billions of years and we can use the energy from the
sun as long as we have a sun. Water flows from high places to lower ones and wind blows
from areas of high pressure to areas of low pressure. We can use the flow of wind and water
to generate power and we can count on wind and water to continue to flow. Some examples
of biomass energy are burning something like wood or changing grains into biofuels. We can
plant new trees or crops to replace the ones we use. Geothermal energy uses water in the
rocks that has been heated by magma. The magma will heat more water in the rocks as we
take hot water out.
Even renewable resources can come with problems, though. We could cut down too many
trees or we might need grains to be used for food rather than biofuels. Some renewable
resources have been too expensive to be widely used or cause some types of environmental
problems. As the technology improves and more people use renewable energy, the prices may
come down. And, as we use up fossil fuels, they will become more expensive. At some point,
even if renewable energy is expensive, nonrenewable energy will be even more expensive.
Ultimately, we will have to use renewable sources (and conserve).