Generating Power from Solar Energy

How Sunlight is Converted to Electricity Using Photovoltaic Process

Solar power is electricity that is generated from sunlight, and is a common choice of renewable energy for households and for large companies. There are two basic forms of solar power in current use: photovoltaics and solar thermal power.

Photovoltaic Solar Power

Photovoltaic systems, such as conventional solar panels, directly convert sunlight into energy using the principles of the photovoltaic effect. The photovoltaic effect takes advantage of the properties of semiconductor materials, with silicon being the primary material used in photovoltaic solar cells. When photons strike the solar cell, electrons in the semiconductor material are shaken loose, allowing them to flow as electricity. This electricity is direct current (DC), and can be directly used to charge batteries, or can be connected to an inverter to power alternating current (AC) components, or to be connected to the local electrical grid.

Traditional photovoltaic systems are based on silicon. Silicon ingots are sliced into wafers that are fabricated into cells. Cells are combined into modules, which are packaged into end-user systems. Silicon-based solar cells have efficiencies of approximately 14-19%. However, newer systems that use gallium arsenide, another semiconductor material, can be made into thinner and more flexible modules. These "thin film" modules can presently produce efficiencies up to 30%, but currently cost more to fabricate than traditional silicon-based modules.

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