Northern Arizona Wind & Sun
Electricity from the sun since 1979
Solar Electric Panels
Solar Electric Panels (PV Panels)
What is a solar panel?
A solar electric panel, often called a PV panel is basically a set of treated silicon cells arranged in a series string that produces electric power when exposed to light. There are three common types of solar panels manufactured. Briefly, they are:
- Monocrystalline - made from a single large crystal, cut from ingots. Most efficient, but also the most expensive. Somewhat better in low light conditions (but not as good as some advertising hype would have you believe).
- Polycrystalline - basically, cast blocks of silicon which may contain many small crystals. This is probably the most common type right now. Slightly less efficient than single crystal, but once set into a frame with 35 or so other cells, the actual difference in watts per square foot is not much.
- Amorphous - "thin film", here the silicon is spread directly on large plates, usually of something like stainless steel. Cheaper to produce, but often much less efficient, which means larger panels for the same power. Unisolar is one example.
- Vaporware - this is the 4th type - the one that pops up in the news about every 3 months, proclaiming the next major breakthrough that will make plastic spray on solar cells that will cost around 5 cents a watt, or some similar claim. Well, after almost 30 years in this business, we are still waiting for one of those to actually reach production, and I suspect we will be waiting for another 30.
For all practical purposes, how the three types work in applications is very similar. What is important when buying panels is to choose the right panel based on how much power you need, how much room you have, and where they will be mounted. They will all do the same thing - make electricity when the sun hits them. Thin film are often less efficient, so will take up more room for the same power, but on the other hand they work better in hot climates due to not losing quite as much at high temperatures.
You will see some manufacturers and websites claiming that panel XX is better because it is more efficient at low light. While it is true that monocrystalline ARE better, the difference in average daily production is less than 1%. If you have low light, you also have low sun energy. So converting 15% of very little is not much better than converting 14% of very little. So, yes, it is true, but about #18 on the list of things to worry about when buying solar panels.
The purpose of this section is some basics on actually using solar panels in practice, so we are not going to get into the theory of it. For more detailed information about solar cells and how they work, see Photovoltaic Basics at EERE.
To be continued...
Our complete listing of all solar panels is here
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Last updated
Tuesday, April 19, 2005