Energy Sources
Gateway – Energy and the Environment
© 2011 Project Lead The Way, Inc.
Energy Source Classifications
A resource that can be
A resource that cannot be
A resource that will never
run out.
A resource that cannot be
Any source of energy that is limited and
cannot be replaced when it is used, such
as oil, coal, and natural gas.
Exhaustible Energy Sources
• Limited availability
• Cannot be replaced
• Currently provides 85% of
energy consumed in US
• Fossil fuels - fuels
produced by deposits of
ancient plants and
animals (Oil, coal and
natural gas)
Exhaustible Energy Sources
• It is possible that
readily available oil will
be used up by 2050
• Foreign countries
provide most US oil
• Oil can be used as an
energy source and to
make plastics
Exhaustible Energy Sources
Effect on the Environment
Burning fossil fuel produces air
– Acid rain is rain contaminated by the
by-products of combustion which
condense in our atmosphere. Acid rain
kills plants and trees and pollutes
ponds and lakes, killing fish and
altering the ecosystem.
– Air pollution can cause lung cancer in
Exhaustible Energy Sources
Effect on the Environment
• Greenhouse effect – Greenhouse
gases surround our planet, which
prevents heat produced by the sun
from escaping the earth’s
atmosphere as easily as it once did.
• The greenhouse effect leads to
climate change, which could cause
melting of ice caps and changing
weather patterns.
A resource that can be replaced when
Renewable Energy Sources
• Energy that can be
• Biological materials
that can be grown
and harvested
• Less pollution than
exhaustible energy
• Currently provides
3.5% of energy
consumed in US
Renewable Energy Sources
• Ethanol – Plants such as corn, soybeans,
seaweed, sugar beets, and sugar cane
can be used to make ethanol.
• Methanol is made from coal or renewable
sources like wood, plants, and manure.
• Methanol and Ethanol can be used as a
substitute for gasoline.
Renewable Energy Sources
• Biomass – Waste products like trees,
plants, grains, algae, manure, garbage,
sewage, and paper can be converted into
• Biomass conversion creates
petroleum substitutes and
methane gas.
Renewable Energy Sources
Effect on the Environment
• Substituting biomass for fossil fuels
reduces emissions of greenhouse gases.
• Combustion of biomass produces air
emissions. The amount of emissions
varies widely depending upon the
technology being used.
An energy source that will never run out.
Inexhaustible Energy Sources
• Any energy source
that cannot be used
• Currently provides
3.5% of energy
consumed in US
Inexhaustible - Solar Energy
• Solar energy can be
captured to provide
heating or electrical
• Solar energy is used
in homes, cars,
satellites, and in the
international space
Inexhaustible –
Hydroelectric Energy
• Force of falling water
turns giant turbines to
create electricity
• Hydroelectric power
plants are located
inside dams
Inexhaustible –
Geothermal Energy
• Energy stored in the
earth in the form of
• Geothermal energy
turns water into steam
which escapes
through cracks in the
• Forms geysers and
hot springs
Inexhaustible - Wind Energy
• Wind powers large
turbine generators
that generate
• Wind farms
contain several
large wind turbines
in a location with
strong and
frequent wind
Inexhaustible Energy Sources
Effect on the Environment
• Minimal pollution
or hazardous
waste produced
• Readily available,
without mining or
So Why Don’t We Use More
Renewable and Inexhaustible
• Renewable energy tends to be
remote from where the electricity is
needed, thus transmission is needed.
• Renewable energy does have
environmental impacts associated
with land use.
• Many renewable resources are
intermittent and are not always
available when the electricity is
needed (example: No sunlight at night
for lighting homes and businesses).
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved September 10, 2008, from