Oct 1, 2007 5:29 pm US/Pacific
Solar Energy
There is a lot of energy in sunlight and that energy can be converted to electricity with photovoltaic panels. These panels are made up of several photovoltaic cells which are constructed of treated silicon which creates an electrical charge when exposed to sunshine.
Each photovoltaic cell produces just a small amount of electricity, so they are wired together into panels to provide enough current for common household appliances.
Photovoltaic cells come in three basic varieties. Monocrystalline are the most efficient but also the most expensive. They consist of a single crystal cut from an ingot of silicon.
Polycrystalline are the most common and slightly less efficient than monocrystalline. The silicon they are made from have several small crystals.
Amorphous cells are made by spreading the silicon on another material like stainless steel. These cells are cheap to produce but produce significantly less power than the other two types. This means that photovoltaic panels must be larger to produce the same amount of electricity.
Monocrystalline panels are slightly more efficient in low light conditions, but the difference is not significant When choosing photovoltaic panels the most significant factor is the amount of available space. If you have lots of room you can install amorphous panels for less money.
As mentioned above, individual photovoltaic cells are wired together into panels which can produce more electricity. The panels themselves can be wired together in parallel or in series to produce a variety of currents suitable for almost any use.
The panels and arrays produce Direct Current (DC) power so it must be converted to Alternating Current (AC) for most purposes. This is accomplished with an inverter.
The AC current from the inverter can be used to power most household appliances. It can also be connected to the breaker box from the utility company so that solar electricity can act as a backup system to regular power supplies. The advantage of using both systems is that if there is any excess electricity produced by the sun it is fed back into the grid for a credit against the homeowner's electricity bill.
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