Solar power is a renewable energy source --- a clean form of energy --- that converts the sun's radiation into usable energy. The use of solar power helps reduce greenhouse gases, offering an alternative to fossil fuels (see References 1). Solar technology seeks to take advantage of the strength of the energy provided by the sun. Earth receives more energy from the sun in a single hour than the world's population uses in a full year (see References 5).
Photovoltaic or PV, technology uses solar cells arrayed on panels to capture sunlight and convert it into electricity or heat. PV technology is used for a wide range of power needs, from small items such as calculators and watches to larger applications for satellites, homes and businesses. Traditional solar cells are made of silicon, but other materials are coming into use as the technology develops. (See References 2)
Concentrating Solar Power
In large-scale uses, concentrating solar power technologies captures sunlight using arrangements of mirrors to direct sunlight toward receivers, concentrating the sunlight and transforming it into heat. This heat is focused on a fluid, which as it gets hot fuels a turbine or generator that produces electricity. Concentrating solar power is capable of generating high levels of power and is valuable for large-scale needs like providing electricity to large populations served by municipal utilities. (See References 3)
Passive Solar Power
Passive solar power is a way of taking advantage of the sun's resources through the intelligent design of buildings. Passive solar power involves designing buildings so they receive sunlight in a way that reduces the need to consume other energy resources for heat and lighting. Strategic placement of windows so they are exposed to significant sunlight is one common passive solar power design tactic, providing both heat and light during the day. Another common design feature is the use of materials in the floors and walls that capture, store and then release heat from the sun. (See References 6)
One limiting factor of solar power is that access to the sun is not constant. Night and overcast days disrupt the supply of sunlight to solar power devices, and the slant of the sun's rays also vary with the seasons. Different parts of the world have varying amounts of access to sunlight. In the U.S., the southwestern region is most suited for solar power because it receives the strongest, most consistent amounts of solar energy. (See References 4)
- U.S. Department of Energy: Solar
- National Renewable Energy Laboratory: Solar Photovoltaic Technology
- U.S. Department of Energy: Concentrating Solar Power
- U.S. Department of Energy: Solar Energy Resources
- National Renewable Energy Laboratory: Solar Energy Basics
- National Renewable Energy Laboratory: Passive Solar
Tom Gresham is a freelance writer and public relations specialist who has been writing professionally since 1999. His articles have appeared in "The Washington Post," "Virginia Magazine," "Vermont Magazine," "Adirondack Life" and the "Southern Arts Journal," among other publications. He graduated from the University of Virginia.
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