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Photovoltaic or Solar right

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Photovoltaic (PV) or conversion of sunlight photons to electrical current. 

In full sun, measured solar energy is about 100 watts of solar energy per square foot. If you assume 12 hours of sun per day, this equates to 438,000 watt-hours per square foot per year. Based on 27,878,400 square feet per square mile, sunlight bestows a whopping 12.2 trillion watt-hours per square mile per year. A 10 mile by 10 mile solar array can generate enough energy to power the state of California during sunlight. Hydro, Wind, and Kinetic Energy Vaults can power the state for the remainder of the day and night.

Solar panels are now up to 30% efficient, a solar home installation of 2000 sq. ft. can produce up to 20 kilowatts per day, or enough to wipe out the electric bill in full and sell excess power back to your utility, company or supplier. Ref.   www.ecoworld.com/energy-fuels/how-much-solar-energy-hits-earth.html     and       http://www.eia.doe.gov/cneaf/solar.renewables/renewable.energy.annual/

                                                        

Different types of Solar Cells
Monocrystalline and Polycrystalline represent the "traditional" technologies for solar panels. They can be grouped into the category "crystalline silicon".

Monocrystalline (also called Single Crystal) vs. Polycrystalline

 Monocrystalline, or Single Crystal, is the original PV technology invented in 1955, and never known to wear out. Polycrystalline entered the market in 1981. It is similar in performance and reliability. Single crystal modules are composed of cells cut from a piece of continuous crystal. The material forms a cylinder which is sliced into thin circular wafers. To minimize waste, the cells may be fully round or they may be trimmed into other shapes, retaining more or less of the original circle. Because each cell is cut from a single crystal, it has a uniform color which is dark blue.

Polycrystalline cells are made from similar silicon material except that instead of being grown into a single crystal, they are melted and poured into a mold. This forms a square block that can be cut into square wafers with less waste of space or material than round single-crystal wafers. As the material cools, it crystallizes in an imperfect manner, forming random crystal boundaries. The efficiency of energy conversion is slightly lower. This merely means that the size of the finished module is slightly greater per watt than most single crystal modules. The cells look different from single crystal cells. The surface has a jumbled look with many variations of blue color. In fact, they are quite beautiful like sheets of gemstone.

The construction of finished modules from crystalline silicon cells is generally the same, regardless of the technique of crystal growth. The most common construction is by laminating the cells between a tempered glass front and a plastic backing, using a clear adhesive similar to that used in automotive safety glass. It is then framed with aluminum.

The silicon used to produce crystalline modules is derived from sand. It is the second most common element on earth, so why is it so expensive? The answer is that, in order to produce the photovoltaic effect, it must be purified to an extremely high degree. Such pure "semiconductor grade" silicon is very expensive to produce. It is also in high demand in the electronics industry because it is the base material for computer chips and other devices. Crystalline solar cells are about the thickness of a human fingernail, therefore they use a relatively large amount of silicon.

 Thin Film Technologies. Imagine if a PV cell was made with a microscopically thin deposit of silicon, instead of a thick wafer. It would use very little of the precious material. Now, imagine if it was deposited on a sheet of metal or glass, without the wasteful work of slicing wafers with a saw. Imagine the individual cells deposited next to each other, instead of being mechanically assembled. That is the idea behind thin film technology. (It is also called amorphous, meaning "not crystalline".) The active material may be silicon, or it may be a more exotic material such as cadmium telluride.

Thin film panels can be made flexible and light weight by using plastic glazing. Some flexible panels can tolerate a bullet hole without failing. Some of them perform slightly better than crystalline modules under low light conditions. They are also less susceptible to power loss from partial shading of a module. GE (General Electric) in the fall of 2011 will begin manufacturing these panels in the USA, we expect a large drop in the cost of PV when they come online.

The disadvantages of thin film technology are lower efficiency and uncertain durability. Lower efficiency means that more space and mounting hardware is required to produce the same power output. Thin film materials tend to be less stable than crystalline, causing degradation over time. The technology is being greatly improved, however, so we do not wish to generalize in this article. We will be seeing many new thin film products introduced in the coming years, with efficiency and warranties that may approach those of crystalline silicon.

PV experts generally agree that crystalline silicon will remain the "premium" technology for critical applications in remote areas. Thin film will be strong in the "consumer" market where price is a critical factor. As usual, you get what you pay for.

Raw materials

While silicon (doped with boron and phosphorus) is the best know solar cell material it is not the only element solar cells are made out of. Silicon is also the most abundant of the elements used and so far produces the most efficient photovoltaic cells. Here is a list of some of the other type of solar cells:
Gallium Arsenide
Cadmium Telluride
Copper Indium Diselenide

Some of the elements used in solar cells, switching devices, motors and generators are classified as "Rare Earth Elements" available in only a few locations on earth in very small quantities. The continental USA posses some of the highest estimated stocks in the world of these elements. Many of these stockpiles must be strip mined, raising environmental issues which continue to keep us dependant on foreign supplies.

Manufacture and Assembly

As would be expected Asia is the leader in numbers of companies manufacturing solar cells. The USA has 21 companies currently manufacturing solar cells. Most of these manufacturers use the Monocrystalline process including SunPower , the exception is DMSolar which is Polycrystalline. See our comparison of manufacturers and types on the top left for more information.

     Recover your total investment in green energy in 3 to 6 years or less with our Smart Kinetic Engineering.

                                                        

 

Wake up America

Oil has been a inexpensive resource for many decades in the USA. With 90% of the easily recoverable oil found, the cost of drilling in sensitive areas of the  USA  is sky-rocketing or prohibited altogether. The political instability in oil producing areas of the world is also causing rapid increases in the cost of oil. 

 

America still has it

 It is predicted that our total green energy production will exceed 20% by 2020. This will  cut our dependency on oil by 5 million barrels per day and creating millions of jobs.

 Renewable resources are abundant in our nation,  including solar, wind, water, and wave kinetic energy. We also have the 3rd largest reserves of rare-earth minerals in the world, the kind that batteries and solar panels use! (97% of these elements now comes from China.) :(

 
  
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