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The
Basics of
Solar Energy Explained
Solar cells absorb sunlight and convert it to electricity.
This is known as the photovoltaic (PV) effect, “photo” meaning light, and “voltaic” from voltage, or electrical potential.
Solar, or PV, cells are most commonly made from crystalline silicon. Each cell is a wafer thin disc that has been subjected to a process called doping. Minute amounts of phosphorous are added to form the very thin upper (or n-type
layer) and minute amounts of boron are added to form the somewhat thicker lower (or p-type) layer.
This process turns the silicon from an insulator into a
semi-conductor and leaves the cell in a state of electrical equilibrium.
That is, until the vital ingredient, sunlight is
introduced.
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Metallic electrical contacts and an anti-reflective coating are added to the front surface of the
cell and an aluminized conductive material is placed on the back surface of the cell. Wiring completes the circuit.
When photons of sunlight strike the cell, electrons are released. They are moved through the silicon and are picked up by the electrical contacts. They move into the external circuit in the form of direct current (DC) - the type of electrical current in a regular battery. The power flows through the load (for example, a light bulb or a motor) and back into the solar cell on the lower side, completing the circuit.
The entire process is self-contained - there are no moving parts and no materials are used up or given
off.
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The solar or photovoltaic cell is the basic component of your solar electric system. Each cell alone produces only a small amount of electricity.
Solar cells are connected together and encased in a protective shell behind a sheet of glass to form a
module or solar panel. Each panel has a metal frame and is equipped with connectors and can be transported and installed safely and easily.
Your solar electric system comprises a number of modules or panels that are variously arranged into a
solar array. The particular configuration chosen will determine the amount of electricity your system produces. |
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Introduction
