World Energy Sources - Southwest High School


World Energy Sources


• Fossil fuel

• Carbon-rich material left over from decomposed prehistoric vegetation

• 37% of the electricity generated worldwide is produced from coal

• Readily combustible black or brownishblack sedimentary rock


· One of the most abundant energy sources

· Versatile

· Comparatively inexpensive

· Can be used to produce ultra-clean fuel

· Can lower overall amount of greenhouse gases

· Leading source of electricity today

· Reduces dependence on foreign oil

· Current supplies may last

200 years


· Source of pollution: emits waste, SO , Nitrogen

Oxide, ash


· Coal mining mars the landscape

· Physical transport is difficult

· Technology to process to liquid or gas is not fully developed

· Solid is more difficult to burn than liquid or gases

· Not renewable in this millennium

· High water content reduces heating value

· Dirty industry—leads to health problems

3.8 days

Natural Gas

• Fossil Fuel

• Found alongside other fossil fuels

• Must be thoroughly refined to derive Methane


· Burns clean compared to coal, oil (less polluting)

· 70% less carbon dioxide compared to other fossil fuels

· helps improve quality of air and water (not a pollutant)

· does not produce ashes after energy release

· has high heating value of 24,000 Btu per pound

· inexpensive compared to coal

· no odor until added


· not a renewable source

· finite resource trapped in the earth (some experts disagree)

· inability to recover all in-place gas from a producible deposit because of unfavorable economics and lack of technology (It costs more to recover the remaining natural gas because of flow, access, etc.)

6.4 days


• Fossil fuel

• Naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons

• Found in geologic formations beneath the earth's surface.


· Oil is one of the most abundant energy resources

· Liquid form of oil makes it easy to transport and use

· Oil has high heating value

· Relatively inexpensive

· No new technology needed to use


· Oil burning leads to carbon emissions

· Finite resources (some disagree)

· Oil recovery processes not efficient enough— technology needs to be developed to provide better yields

· Oil drilling endangers the environment and ecosystem

4.8 days


• Renewable energy

• The conversion of wind energy into a useful form of energy

• Can be done through turbines, mills, pumps, etc.


· Continuous sources of energy

· Clean source of energy

· No emissions into the atmosphere

· Does not add to thermal burden of the earth

· Produces no healthdamaging air pollution or acid rain

· Land can be used to produce energy and grow crops simultaneously

· Economically viable


· For most locations, wind power density is low

· Wind velocity must be greater than 7 mph to be usable in most areas

· Problem exists in variation of power density and duration

(not reliable)

· Need better ways to store energy

· Land consumption


• The generation of electricity from sunlight.

• Photovoltaic cells convert sunlight into electricity.

These are made from semiconductors like crystalline silicon, etc.


· Solar panels give off no pollution after manufacturing.

· Produces electricity very quietly.

· Able to harness electricity in remote locations that are not linked to a national grid


• Prices of highly efficient solar cells can be above

$1000, and some households may need more than one.

This makes the initial installation of solar panels very costly.

· Solar energy is only able to generate electricity during daylight hours.


• Renewable

• The production of electrical power through the use of the gravitational force of falling or flowing water


· Expands irrigation

· Provides drinking water

· Supplies hydroelectric energy (falling water used to run turbines)

· Easier for third world countries to generate power (if water source is available)


· Destabilizes marine ecosystems

· Dam building is very costly

· People have to relocate

· Some dams have to be torn down (Some older ones are not stable.)

· Restricted to areas with flowing water

· Pollution affects water power


• Renewable

• Power extracted from heat stored in the earth.

• From the Greek roots geo, meaning earth, and thermos, meaning heat


• Sustainable

• Nearly emission free

• Very low cost

• Safe

Disadvantages o Can only occur where heated rocks are near the surface of the earth.

o May cause small aftershock earthquakes o Minor damage may take 1000 years to recover.

Possible Future Fuels

0 The production of geothermal energy can occur only in areas where hot rocks lie near Earth's surface


• Renewable energy source

• Biological material that can act as fuel

• The most common example: lumber


• Theoretically inexhaustible fuel source

• When direct combustion of plant mass is not used to generate energy (i.e. fermentation, pyrolysis, etc. are used instead), there is minimal environmental impact

• Alcohols and other fuels produced by biomass are efficient, viable, and relatively clean-burning

• Available throughout the world


• Could contribute a great deal to global warming and particulate pollution if directly burned

• Still an expensive source, both in terms of producing the biomass and converting it to alcohols

• On a small scale there is most likely a net loss of energy--energy must be put in to grow the plant mass

1.2 days


• Certain substances called nuclear fuels undergo fission when struck by free neutrons and in turn generate neutrons when they break apart

• This makes possible a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor


• Relatively little fuel is needed and the fuel is relatively inexpensive and available in trace amounts around the world.

• Fission is not believed to contribute to global warming or other pollution effects associated with fossil fuel combustion


• Possibility of nuclear meltdown from uncontrolled reaction--leads to nuclear fallout with potentially harmful effects on civilians

• Waste products can be used to manufacture weapons

• High initial cost because plant requires containment safeguards

1171 years


• Fusion has occurred naturally for billions of years in stars

• Molecules are made to combine, and then separate, releasing great amounts of energy

• Often called “the future of energy”


• The fuel for fusion reactions are readily available.

Deuterium and Tritium are virtually inexhaustible.

• Fusion produces only helium, a gas that is already in abundance in the atmosphere and will not contribute to global warming.

• Fusion has no problems with dangerous by-products.


Scientists have not yet been able to contain a fusion reaction long enough for there to be a net energy gain.

Many countries are phasing out fusion research because of the failure to reach a breakthrough