by Gloria Jones
(Miami Beach, Florida, USA)
The actual conversion process of the sun’s energy into usable electric power is called photovoltaic or PV for short. The most important piece in the PV puzzle is the semi-conductor. If you think about a regular piece of household wire, it consists of the wire itself, which is a conductor and the plastic cover on the wire which is the insulator.
The insulator is what protects us from being electrocuted as the electrons are not able to pass through the insulating material. A solar cellcontains what is essentially a hybrid of the two or a “semi-conductor”. A semi-conductor is something which:
1. Has the properties of am insulator.
2. When exposed to light or heat can also act as a conductor.
By creating both positively and negatively charged semiconductors and then linking them together with a conductive material (i.e. wire) which completes the circuit, an electric current is created. This current can then be directed to what is called the BOS (Balance of System).
The BOS consists of everything except the solar panels. Depending on whether your solar system is stand alone or grid tied, the BOS components will vary somewhat but can include the following – wiring, connectors, mounting structures, fuses, inverters, batteries and digital displays.
When the first solar cell was developed in 1818 by Charles Fritts, it had an efficiency rating of around 1%. This meant that of all the solar energy captured by the cell, only 1% was actually converted to usable energy. Today, the efficiency of solar cells range between 6% for silicon based cells to just under 44% for cells made from exotic materials such as gallium arsenide.
Like all things in life, there is a sweet spot where efficiency and price are at a happy medium. While exotic material solar cells are almost 8 times more efficient than lower grade cells and 2 times as efficient as multi-crystalline cells, they also cost 100 times as much. This makes exotic solar cells an unrealistic alternative for the average consumer application.
Historically, the cost of professionally installed solar systems has been prohibitively expensive for the average home owner. The high cost is slowly coming down as improvements in manufacturing efficiency and reduced production costs due to increased volume begin coming into play.
In the mean time, a considerable market had developed for DIY solar cellpower. While these types of systems are not necessarily as efficient as commercially available systems, their cost is significantly lower. This makes them very attractive to home & cabin owners as well as recreational vehicle owners and hobbyists who are interested in reducing their energy costs with minimal payback time.
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