STATION 1
ENERGY SOURCES
Fossil fuels are nonrenewable.
Humans get much of their energy by burning coal, oil, and natural gas. We call
these energy resources fossil fuels because they are formed from plants and
animals that died millions of years ago. Because fossil fuels take millions of years
to form, they are nonrenewable energy resources. Eventually, we will use them all
up.
Fossil fuels have many advantages. They are relatively inexpensive to obtain and
use. They produce large amounts of energy when burned. They are
nonrenewable, yet they are still plentiful. Scientists estimate there are still
hundreds of billions of tons of coal and hundreds of billions of barrels of oil
remaining on Earth.
Fossil fuels also have many disadvantages. Because they are nonrenewable, we
cannot rely on them indefinitely. Some scientists estimate that within the next
50–100 years, our supplies will run out. Burning fossil fuels also releases
pollutants into the air. One of these pollutants is carbon dioxide, a gas that traps
heat at Earth’s surface. Scientists agree that adding carbon dioxide to Earth’s
atmosphere is a cause of global warming. It is also very difficult to remove some
fossil fuels from Earth without damaging the environment from the mining and
drilling that takes place. For example, as we move oil through pipes and on ships,
it sometimes spills. Oil can also leak from our vehicles. These accidental spills can
cause lots of damage to wildlife and the environment. So can improperly
disposing of oil—never dump oil down a drain!
We burn fossil fuels at power
plants. The energy released
by the fuels as they burn is
converted into electricity and sent
to homes and other buildings.
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STATION 2
ENERGY SOURCES
Nuclear power is a nonrenewable energy source.
All matter is made up of tiny particles held
together by forces called bonds. Humans can
break these bonds to release large amounts of
energy called nuclear power.
One of the most important advantages of
Between 15 and 20% of the world’s
nuclear power is that it does not produce
electricity is produced at nuclear
power plants.
much air pollution or contribute to global
warming.
(Most of the gas released from a nuclear power plant is water vapor.)
The fuel needed to produce nuclear power is relatively inexpensive, and
it releases much more energy than fossil fuels. However, nuclear plants
are expensive to build and maintain. Although they do not pollute the
air, they produce large amounts of dangerous waste that is not easy to
store or get rid of. Nuclear power is also nonrenewable—we use up the
fuel more quickly than nature can make it.
When some people think of nuclear energy, they remember terrible
accidents that have happened at nuclear power plants. In 1986, a large
nuclear power plant in Chernobyl, Ukraine, released dangerous
materials into the surrounding environment. Many plants and
animals—including people—died or were seriously injured. In 2011, an
earthquake caused the release of dangerous materials at a nuclear
plant in Fukushima, Japan. Nuclear power plants in the United States
and other countries are regulated and inspected routinely. Still, the risk
of terrible accidents causes some people to oppose nuclear energy.
Nuclear power plants are dangerous because
they contain radioactive materials. When a
substance is radioactive, its particles are breaking
apart. These particles can damage nearby
organisms.
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STATION 3
ENERGY SOURCES
Renewable energy resources can replace nonrenewable ones.
In the United States, we use many more nonrenewable energy resources than
renewable ones. In the past few years, energy use from several renewable energy
resources has greatly increased. Let’s take a look at some of the most commonly
used renewable energy resources.
Solar Power:
Sunlight is probably the most important energy resource on Earth. It warms the
planet and provides plants with the energy they need to make food. Humans can
also use sunlight to heat buildings and power machines. Today, many scientists
are working to find more and better uses for solar power. Unlike most energy
sources, solar power does not produce air or water pollution. Although the Sun
shines only part of the time, batteries allow us to store solar energy to use later.
However, solar panels are expensive. The process of making them can produce
harmful waste, and old solar panels can be difficult to safely dispose of.
This solar panel collects
and stores sunlight. The
energy is then used to
power this streetlight.
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STATION 4
ENERGY SOURCES
Geothermal:
The Sun is Earth’s main source of energy. However, our planet also produces its
own energy deep beneath the surface. We call this geothermal energy. (Geo means “Earth” and thermal means “heat.”) Geothermal energy is a clean energy
source that produces little waste. Geothermal plants are relatively inexpensive to
run, and they can generate power around the clock. However, the initial cost of
building a geothermal plant is high, and they can exist only where lots of Earth’s
heat rises to the surface—like near hot springs or geysers. Additionally,
geothermal energy is not easy to transport
Some geothermal energy comes
from warm water and rock near
Earth’s surface. Other energy
comes farther down, from
extremely hot, molten rock
(magma).
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STATION 5
ENERGY SOURCES
Hydropower:
Hydroelectric plants use the energy of flowing water as it moves downstream.
(Hydro-means “water.”) The water spins turbines to produce electricity. Dams are
often built near hydroelectric plants. The dams control the flow of water—the
dams can be shut off if power is not needed. Hydropower is a clean energy source
that does not pollute the environment. Yet, dams are expensive to build and
maintain. They can cause flooding and disrupt the surrounding ecosystem by
slowing or even stopping the flow of water in a river. In addition, power plants
sometimes release heated water back into the ecosystem. Plants and animals
living downstream of the dam may not be able to adapt to these changes.
This dam on Lake Travis produces
hydroelectric power in central Texas.
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STATION 6
ENERGY SOURCES
Wind:
Like flowing water, blowing air can spin turbines to produce
electricity. These energy resources convert the motion, or kinetic
energy, of natural processes into electrical energy we can use.
Also like hydropower, using wind energy does not produce
pollution. However, wind turbines can be noisy and expensive to
build. As they spin in the air, they can harm birds flying nearby.
Blowing air moves
these windmills,
or turbines. As the
turbines move, they
generate electricity.
Biomass:
Biomass refers to living or recently living organisms we can use as energy
resources. For example, corn plants are converted into a fuel called ethanol that
can replace gasoline in cars. Biomass is a cheap resource that can be made from
many common waste products. Unlike fossil fuels, biomass is renewable—we can
grow new plants quickly. However, burning biomass releases several harmful
pollutants into the air. It also releases less energy than burning the same amount
of fossil fuels.
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What do you know?
Study the photographs of the energy resources below. Identify each energy
resource as renewable or nonrenewable. Then, list two advantages and two
disadvantages for each resource.
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