PV cells - Photovoltaic

cells http://science.howstuffworks.com/environmental/energy/solar-cell1.htm

·         photo meaning "light" and
·         voltaic meaning electricity
·         converting sunlight directly into electricity
·         made of 2 semiconductors (one layer containing a positive charge, the other a negative charge)

How does a PV cell work?

1.      Light strikes the cell

2.      A certain portion of it is absorbed within the semiconductor material

3.      Energy of the absorbed light is transferred to the semiconductor

4.      Energy knocks electrons loose, allowing them to flow freely

5.      One or more electric field that acts to force electrons freed by light absorption to flow in a certain direction

6.      Flow of electrons is a current and placing metal contacts on the top and bottom of the PV cell

7.      Draw current off for external use

* This current, together with the cell's voltage, defines the power that the solar cell can produce.

Benefits

 http://www.energysavingtrust.org.uk/Generating-energy/Choosing-a-renewable-technology/Solar-panels-PV

·         Cut your electricity bills, unlimited access to free sunlight

·         Cut your carbon footprint: solar electricity is a green, renewable energy that doesn't release any harmful carbon dioxide or other pollutants.

Disadvantages

http://www.greenenergysavingtips.com/pros-and-cons-of-photovoltaic-pv-panels-solar-energy/

·         Limited efficiency levels as compared to other renewable energy sources – such as solar thermal

            (PV systems have a relatively low efficiency level ranging between 12-20%)

·         Low voltage output or fluctuation in PV electric current may lead to increased waste of electricity since it cannot be transmitted