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Basic overview
Solar technology
Certain materials convert light energy into electrical energy at the atomic level. This is called photovoltaic (PV) effect. The photoelectric effect is the basic physical process by which a PV cell converts sunlight into electricity. When light shines on a PV cell, it may be reflected, absorbed, or pass right through, but only the absorbed light generates electricity
Photovoltaic cells - the building blocks
Solar panels are made of photovoltaic (PV) cells.
A photovoltaic (PV) or solar cell is the basic building block of a solar electric system.
Photovoltaic cells are made of semiconductor materials, usually silicon alloys. As researchers develop new types of photovoltaic (PV) cells and modify existing designs, the changes made to the cells led to improved characteristics relating to current, voltage, overall power, and the efficiency in converting the sun's energy into electrical energy.
The semiconductor material are deposited or arranged in various structures, to produce solar cells aiming optimal performance. Currently there are three main types of materials used in solar cells. The first type is silicon, which can be used in various forms, including single-crystalline, multi-crystalline, and amorphous. The second type is polycrystalline thin films, made of the deposition of specific materials such as copper indium diselenide (CIS), cadmium telluride (CdTe), and silicon, on a a substrate material such as glass, stainless steel, or plastic in virtually any shape. Finally, the third type of material is single-crystalline thin film, focusing especially on cells made with gallium arsenide.
An individual PV cell is usually quite small, typically producing about 1 or 2 watts of power. PV cells are connect together to form larger units called modules or solar panels. Solar panels can be made in different sizes and shapes.
Modules, in turn, can be connected to form even larger units called arrays, which can be interconnected to produce more power.
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Photovoltaic systems
Together with the PV modules or arrays other components are added to take the direct-current electricity produced by modules and convert to alternate-current electricity by the invertor. If energy storage is desired, batteries are also added. All these components are referred to as the "balance of system" (BOS) components.
Combining modules with the BOS components creates an entire PV system. This system is usually what is needed to meet energy demand, such as powering a water pump, appliances and lights in a home, or, in larger scale, supply electricity to a whole community.
Solar systems can be on-grid, to generate electricity for home or business and route the excess into the electric utility grid or off-grid, usually installed in remote areas where utility grid in unavailable.
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Concentrating systems
PV systems can be classified into two general categories: flat-plate systems and concentrator systems.
Concentrating solar power (CSP) technologies use mirrors to reflect and concentrate sunlight onto receivers that collect the solar energy and convert it to heat. This thermal energy can then be used to produce electricity via a steam turbine or heat engine driving a generator
Concentrating solar power technologies can generate electricity at relatively low cost and deliver power during periods of peak demand. In addition, integration with low-cost thermal storage adds significant value to the energy delivered from CSP plants. The public is becoming more familiar with the availability, benefits, and economic feasibility of CSP as researchers are discovering ways to reduce costs and improve efficiencies. Consequently many utility companies are including concentrating solar power in their power-generation portfolio, reducing the dependence on fossil fuels
The following links lead to the US Dept of Energy (DOE) for related subjects: