The energy from the sun can serve many purposes. One of them is to generate electricity. This is what we call solar electricity. Using solar panels, the sunlight is directly converted into electricity. This process is called the photovoltaic effect (abbreviated as PV; See Photovoltaic effect).
PV is short for photovoltaics (photo=light, voltaics=electricity). PV is a semiconductor-based technology used to convert light energy into direct current (dc) electricity, using no moving parts, consuming no conventional fuels, and creating no pollution.
The use of solar electricity has many advantages. It is a clean, quiet and reliable energy source.
Nowadays the use of solar electricity is widespread. In remote areas where there is no connection to the electricity grid this form of solar energy is used to meet electricity demand of households and to power waterpumps and vaccine refrigerators. These systems often use batteries to store electricity. But also calculators, telecommunication systems or buoys at sea are operating with solar electricity.
Another application of solar electricity is power generation for houses, offices and other buildings or supplying electricity to the electricity grid by solar electricity systems.
What does PV cost; aren't PV systems expensive?
Everything is relative. Using a PV system can be more expensive than buying power from the local utility, through the electrical outlet in your wall. However, it is dramatically less expensive than running a power line to a site currently without service (off-grid homes, more than 0.25 mile [or 0.4 kilometer] away from power, or a mountain-top communications system). PV modules can cost less than US$5/watt, in quantity, but that is only one part of a system cost. A system could include design costs, land, support structure, batteries, an inverter, wiring, and lights/appliances. The total system cost could be as low as US$7/watt or as much as US$20/watt or more, depending on the complexity. Every application is unique, and generalizations on cost are difficult to make.
Solar electricity can be used in three basic forms:
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No electricity grid is available or a connection to the grid is not made. Solar panels produce electricity for lighting, TV and radio, water pumping, a refrigerator or tools. Normally, electricity storage is provided by batteries to secure energy supply at night and other times when the solar panels don't produce electricity. |
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In areas where an electricity grid is available, solar panels can be used to produce your own clean electricity by using daylight and roof space (or other unshaded space). |
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The system is connected to an electricity grid of poor quality. In case of blackouts solar electricity cover the electricity demand. |
Remote Residential
Around the world, there are more than 100,000 off-grid residential PV systems, as of 1996, including tens of thousands of vacation homes in Scandanavia. These systems, typically from one module to one kilowatt, comprise the PV modules, batteries, charge controllers, and assorted loads (lights, radio/TV, refrigerator).
Village Power
In developing economies, there are hundreds of thousands of villages that currently have no access to electric power or that use diesel generators, which are expensive to fuel, difficult to maintain, and environmentally harmful. PV village power systems provide electricity for domestic, community, or industrial activities. PV can also be used with diesel generators as part of hybrid systems.
General Stand-Alone Systems (Lighting, Cathodic Protection, etc.)
Photovoltaic systems can supply electricity in areas where there is no electric grid, or where connecting to that grid would be too expensive.
Water pumping: PV systems can replace hand pumps or large engine-powered water pumping systems. In many pumping systems, no batteries are required, as the pumped water storage provides that function.
Cathodic protection: Metal corrosion causes damage to pipes, tanks, well heads, wharves, bridges, and buildings. PV-generated electricity prevents electrolytic corrosion of such structures.
Communications: PV systems have been powering remote communications systems, such as microwave repeaters, television and radio transmitters and receivers, telephone systems, and small radios, since the mid 1960s. These systems provide reliable, low-maintenance power for these remote systems.
Lighting and small appliances: PV can be used to light homes, operate TVs and radios, or power street lights. In the developing world, improving indoor lighting allows small industry to expand, replacing kerosene lanterns and improving indoor air quality.