Solar Energy: The Real Facts
Friday, 07.13.2007, 10:42pm (GMT)
Most power plants in the United States and all over world are using
fossil fuels to operate and generate electricity. Fossil fuel has been
used as an energy source as long as man has learned to generate power.
Fossil fuel has been around for ages and when man started using this
energy sources no one though about the consequences. Fossil fuels will
run out and there will be a shortage of it in near future. This
shortage in fossil fuel will have its affect on our daily live and
various industries. Today we see some of these affects already, fossil
fuel prizes are raising and electricity is becoming more expensive.
Although fossil fuels are more scares, to need for fossil fuels will
still be here and will not decrease in near future. To solve this
shortage of fossil fuels we will need to look for other possibilities
for our energy demand.
Fortunately, alternative energy sources are growing in interest. For
instance, locations with high water falls are experimenting on building
a hydro-electric power plant, which turns out to be successful. Other
locations with high wind speed make use of a power wind mills that can
convert wind power into electricity. Also thermal and tidal powers are
good alternatives.
Solar energy is also one of the energy sources that is gaining in
interest. Solar energy has steadily been growing. Today solar energy is
widely used in the US and the advantages are numerous. Our solar energy
source, the sun, its life span is estimated to be another 4.5 billion
years. It is fair to say that this energy source is almost endless.
Rate of Energy from the Sun
The sun’s radiation reaches a certain unit of area in space in the
region of the Earth’s orbit and is estimated to be at 1,400 watts per
square meter. Out of this, photovoltaic cells (also known as solar
cells) can capture 19 to 56 watts per square meter (for 15% efficiency)
or an equivalent of 0.45 to 1.35 kilowatt per hour (kWh) in an annual
day and night average.
Therefore, if there would be more area that will be covered by several
solar panels, these panels can produce slightly more energy in the form
of electricity than what is currently available from oil, gas, and
other sources of energy combined (assuming 8% solar cell efficiency).
Conversion of Solar Energy
There are two ways of conversion of solar energy. First is the direct
solar energy which involves only one conversion into a usable form. For
instance:
• Sunlight hits the solar cell, converting it into electricity.
• Sunlight hits the absorber surface of a solar thermal collector,
converting into thermal energy which can be used to heat homes during
cold season.
The second is the indirect solar energy which involves more than one conversion to reach a usable form. For instance:
• Plants use photosynthesis to transform solar energy to chemical
energy, which can be burned later as fuel to generate electricity (also
known as bio-fuel technology).
• Hydroelectric dams and wind turbines are indirectly supplied by solar
energy through its interaction with the Earth’s atmosphere.
Pros and Cons of Solar Energy
Just like any other types of energy resources, solar energy has its ins and outs.
Pros:
• Pollution-free.
• Solar facilities can be run with little extra input or maintenance.
• It is abundant. As mentioned earlier, most of the inhabited areas here on Earth can be reached by sunlight.
Cons:
• Although it is abundant, non-tropical locations can receive little
sunlight. Thus, power that will be produced in these locations is a
minimum.
• Only during daytime thus not available during night time.
• Photovoltaic cell technologies generate direct current (DC) power
which needs to be converted to alternating current (AC) power used in
distribution grids.
Once massive development of the use of solar energy is materialized,
expect that every household or industry in the world will now be
powered by solar energy. It is not just a dream, it will be a dream
come true.
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