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How Solar Energy Works
Solar panels convert sunlight into electricity. The biggest source of light is the sun and the sun is known as “Sol” by astronomers. Ergo, “solar”. The other term associated with solar panels is “photovoltaics” (PV) or photovoltaic cells which basically means, “light-electricity”.
As a general statement, a solar panel is a packaged interconnected assembly of solar cells/conductive material. Each panel is limited by how much electricity it can produce but it can also be used in conjunction with other panels for more power if desired. The connection of individual solar panels as a “group” is called an array. You could have one panel, or one array, or several arrays. Or one big array. There are all kinds of mechanics available for putting together and securing an array.
Important Note: As mentioned, solar panels run on light, not heat, they convert sunlight into electricity. Heat slows them down which is why ventilation is important.
Solar power panels are notoriously inefficient. There are lots of technical reasons for that that can be found elsewhere if inquiring minds want to know. Officially, “efficiency” is called the “sunlight conversion rate”. And, that rate can be anywhere from converting 5% to about 21% of the sunlight to electricity with today’s solar panels. It’s pretty obvious that a 45 watt 5% sunlight conversion panel just isn’t going to perform as well as a 45 watt 18% sunlight conversion panel.
So, no matter how something is built, look for the sunlight conversion rate, or efficiency rate. Since higher efficiency often costs more, you must decide if that increase is worth the difference. It isn’t always worth it depending on what you need and how you use them. But, conversely, sometimes the cost of solar panels isn’t that much higher for a much better panel, which would then be a better choice for the solar electric power you need.
Monocrystalline (or multi-crystal) silicon panels
These panels are made from one continuous sheet of silicon with metal attached to the edges increasing conductivity. Their efficiency rates are in the 14%-18% bracket. They’re more expensive and more efficient.
Polycrystalline silicon panels
These panels have an efficiency rate of around 12%-14% so they’re not quite as efficient as the above. But they’re good. They’re put together with individual PV cells, lots of them. Metal is also attached on the edges to aid in conduction and also hold the cells together. When an individual cell is damaged you could theoretically replace it without replacing the whole panel. Their cost is less than the monocrystalline panels.
String ribbon silicon panels
These are put together very much like the polycrystalline panels but with added technological differences. Some people put the efficiency rate at around 12%-14%, some considerably higher. The difference in technology does allow for a lower manufacturing cost than the polycrystalline solar panels which should translate into a lower market cost.
Amorphous silicon panels
Last and least are the amorphous silicon panels with a 5%-6% efficiency rate, the lowest of any type of solar panel. They’re made from a thin flat piece of conductive metal like copper with a thin layer of silicon film over the top. They’re inexpensive to produce, relatively cheap to buy but aren’t big on energy production. Of course, if you only want to run a couple of light bulbs, etc., these solar panels could be just the thing. Amorphous silicon is being used in new ways such as in a metal roof application which has very interesting possibilities.
Choosing a Solar Panel
While technology is changing rapidly there are generally four different core kinds of solar panels at the moment.
The difference between them is how they’re made which ultimately affects their efficiency. “Efficiency” means the percentage of total light that hits the panel that can be changed into electricity.