Renewable & Inexhaustible
Energy Sources
Control Power
CVHS
Energy vs. Power
Energy is defined as “the ability to do work”
Power is a term used to describe the measure
of work being done (rate)
Energy & Society
Without energy, Life would not be
possible
Energy not only powers modern
technologies including transportation,
etc., but is also necessary to power
living organisms (people, animals,
plants, etc.)
Sources of Energy
Nonrenewable
Renewable
Inexhaustible
Nonrenewable Energy
This is a source of energy that once used,
cannot be replenished
Examples: Coal, Natural gas, Nuclear, etc.
Renewable Energy
This is a source of energy that can be
replenished if it is used.
Examples: wood, ethanol, food, etc.
Inexhaustible Energy
This is a source of energy that can be
considered permanent (at least for a few
million more years).
Examples: Sun, Wind, Waves, Geothermal
Renewable & Inexhaustible Energy
To combat the ill effects, and high costs
of nonrenewable energy sources, new
technology must be developed.
These new energy technologies
must heavily rely on
renewable and
inexhaustible resources
in order to be sustainable
Renewable Energy Sources
Animals
Plants
Biomass
Animals
Source of food
Source of work energy (especially in
underdeveloped countries)
Why are animals considered to be
renewable and not inexhaustible?
Plants: Wood
One of the earliest used fuels
Despite a decline in the 1900’s, wood is once
again a popular choice as a home heating
fuel.
Can be converted to “wood gas” (methanol)
in liquid or gaseous forms
Concerns:
Trees must be immediately replanted to
compensate for long growth periods
Burning wood releases pollutants
Creosote Build-up
Plants: Alcohol
Can be produced from a variety of plant life
including: Corn, Sugar beats, Sugar cane, and
wood.
Used to run internal combustion engines, etc.
(E85, Regular gas usually includes ~ 10%
ethanol)
Major Forms: Ethanol & Methanol
Concerns:
Corn ethanol cuts in on a source of food
Still produces pollution
Biomass
Bioconversion is a process that burns or
converts waste organic material into a
useable form of energy
Incinerators burn biomass to produce
electricity
Anaerobic Digestion can be
used to produce methane
gas which can be burned
like Natural Gas or Propane
Inexhaustible Energy Sources
Sun
Water
Wind
Geothermal
Sun
Most energy sources
derive their stored
energy from the sun,
including plants, trees,
wind, etc.
The sun provides an
almost limitless source
of energy that can be
collected to produce
heat (thermal) or
electrical energy.
Water: Hydroelectric
Used for decades as an energy source for
electricity generation
Uses the power of moving water to spin a
turbine, which turns a generator to produce
electricity
Most large scale
sites have been
developed in the
US, meaning that
only smaller sites
may yet be utilized
Three Gorges Dam Expected Finished output 22,500 MW
Water: Tides & Waves
Uses the force of
tides and waves to
produce electricity
Very clean, but may
interfere with
natural ecosystems,
and fishing locations
Tide generators can
only be used in
certain locations
Water: OTEC
Uses the temperature differential
between surface water and deep water
(energy stored in water by the sun)
Warm water creates steam (spins
turbine) cool water condenses steam
back into a liquid
Can be used to produce electricity at
remote ocean locations
Problems:
Can only be used in certain locations (temp.
differential)
Dumping large amounts of cold water into the
ocean can damage the ecosystem
Water: Hydrogen
Hydrogen is a very energetic & clean fuel
source, but is scarce in its natural state
Water molecules can be split to produce
Hydrogen and Oxygen
Pyrolysis
Requires large amounts
of energy
Two Forms: Electrolysis
& Pyrolysis
Wind
Used for hundreds of years as a
mechanical energy source
Now used to produce electricity in large
scale wind farms, and residential
settings
Problems
Noisy
Large areas of land/ sea
required
Geothermal
Uses steam from the
earth to spin a turbine
and produce Electricity
Problems:
Loud
Smelly
May produce Pollution
Heat pumps can also be
used to heat water to ~
55° F for home heating
Problems
Must be used in
conjunction with another
energy source
Conclusions
Dependence on Fossil fuels must
change sooner or later due to
environmental concerns, and the fact
that they will someday run out
Many forms of energy will need to be
implemented to replace fossil fuels
Each, has problems associated with it
that must be weighed against its
benefits