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Renewable and Alternative
Energy Sources
World Wide Energy Production
15.2%
alternative
84.8%
fossil
fuels
World-wide, with the
exception of coal, which
has known reserves that
will last a couple of
centuries, the known
reserves of oil are
expected to be exhausted
in your lifetime...
Clearly, alternative energy
sources are needed for
the future
Alternative Energy Sources
alternative energy – a
form of energy derived
from a natural source that
could replace the use of
fossil fuels.
renewable energy - any
natural resource that can
replenish itself over a
relatively short amount of
time (a human lifetime).
Alternative Energy Sources
We will look at:
Solar energy
Geothermal power
Hydroelectric
Tidal Power
Wind energy
Biomass and Biofuels
Alternative Energy Sources
Solar Energy
The Sun is free (nobody owns or controls it)
In principle, the amount of solar energy that
reaches the Earth’s surface could provide for
all human energy needs forever
Solar Energy
The distribution of solar energy over the
continental U.S. in watts per square meter
The desert regions of the southwest U.S.
receive the most sunlight
Clean Solar Energy
Solar energy is clean energy
It produces no hazardous solid, liquid or gas
wastes
It does not create water or air pollution
Largest Solar Plant in the World
http://america.aljazeera.com/articles/2014/2/13/largest-solar-plantintheworldopensinusasindustrygrows.html
Disadvantages
• Solar panels are
expensive.
• When it is cloudy or at
night there is not enough
light.
• Some people don’t like
the look of solar panels.
What is it?
• Solar power
uses energy
from the Sun.
• Solar panels
transfer the
Suns energy
to heat water.
Advantages
• The energy from the Sun
is free.
• The sun does not produce
greenhouse gases.
• The sun will always be
there during our lifetime.
Geothermal PowerMagma rising from the mantles brings unusually hot
material near the surface
Heat from the magma, in turn, heats any groundwater
This is the basis for generating geothermal energy
Geothermal Power
The steam and/or hot water is used
to create electricity or for heating
Geothermal Power Plants
Worldwide, there are now about 40 geothermal
power plants, especially in Japan, Mexico and
the Philippines
Note that
most
geothermal
power
plants are
built along
plate
tectonic
boundaries
Klamath Falls, OR
http://climatesolutions.org/news/oregon-town-uses-geothermal-energy-to-stay-warm
Disadvantages• There are not many places
where we can build
geothermal power
stations.
• Harmful gases and
minerals may occasionally
come up from the ground
below. These can be
• difficult to control.
What is it?• Rocks
under the
ground are
hot.
• Water can
be pumped
through
these hot
rocks and
warmed up.
Advantages
• Geothermal energy does
not produce greenhouse
gases.
• The energy source is
free and will not run out.
HydroelectricHydroelectric is a very clean, pollution-free,
renewable energy source
The water is not consumed, but rather simply
passes thru the generating equipment, and since
several dams may occur along the same river, the
water can be reused and reused
HydroelectricA cross-section of a typical hydroelectric dam
Water flows down the penstock, turns the
turbine blades which power the generators
HydroelectricWater use for generating hydroelectric power is
totally dependent on the available water (duh!!)
The Glen Canyon Dam in Utah is the classic
example of building too big of a dam for not
enough water
Disadvantages• The dam is expensive to
build.
• By building a dam, the
nearby area has to be flooded
and this could affect nearby
habitats.
• If it does not rain much we
may not have enough water
to turn the turbines.
What is it?
• Flowing
water is
used to turn
a turbine
which
generates
electricity.
Advantages• When the electricity is
generated, no greenhouse
gases are made.
• The water used is free.
• It is a renewable energy source.
Tidal Power
All large bodies of water, including the oceans
and large lakes, have tides
Tidal power captures the energy contained in
moving water mass due to tides
Tidal Power
Turbines can be place on the ocean floor, for
example at the entrance of a bay, where the
flowing water can turn the fan to generate
electricity
Tidal PowerAnother option is to use under water turbines,
which is like an underwater wind farm
This is currently being tested offshore of Scotland’s
Orkney Islands
The ebbing and surging tidal flows turn 100 foot
propellers, which each produce 1 megawatts of
electricity
Disadvantages• A dam to make the water
flow through the generators
might be needed.
• Plants and animals that live
nearby might get harmed
• The tides only happen twice
a day, so can only produce
electricity at that time.
What is it?
• Solar power
uses energy
from the
Sun.
• Solar panels
transfer the
Suns energy
to heat
water.Advantages
• Tides are free and will not
run out.
• No greenhouse gases are
produced.
• It is reliable because we
know exactly when the
tides happen.
The wind is free, commonly available and
can provide clean, pollution-free energy
Today’s wind-turbines are very high tech
Wind Energy
The numbers indicate the percentage of
1990 regional electricity demand that full
utilization of wind energy could meet
Clearly, the great plains have significant
wind energy potential
Wind Energy
It would take about 1000 one-million watt
windmills to equal the energy output of one
sizable fossil fuel power plant
Wind Energy Limitations
The windmills can
be noisy
And they are hard
on migrating birds
Disadvantages
• Lots of wind
turbines are needed
to produce enough
power.
• Turbines can only be
put in windy areas.
• It is not always
windy.
• Some people don’t
like the look of the
turbines.
What is it?
• Wind turbines
are used to
generate
electricity from
the wind.
• The wind turns
the large
blades and the
blades turn a
generator.
Advantages
• Wind is renewable.
• Wind is free.
• No greenhouse gases
are made.
• There are few safety
risks.
Biomass energy is derived
from organic matter
Stoves that burn wood are
the classic example
In fact, there had been a
20-25% increase in the use
of wood stoves over the
past several decades
Biomass Energy
Biofuels differ from other renewable energy sources,
such as wind, hydroelectric, geothermal and solar,
as they are primarily used in the transportation
sector and are derived from recently living matter,
both plant and animal
Biomass Fuels or Biofuels
Disadvantages
• Inefficient (only 30%
efficiency).
• Releases harmful
solid carbon
particles into the
atmosphere.
What is it?
• Biomass, is a
renewable
energy source
made of
biological
material from
living, or
recently living
organisms.
• Energy is
released by
combustion
(burning).
Advantages
• Produces less pollution
than fossil fuels.
• Does not cause acid
rain.
• Can be found locally.
• It is renewable.