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The sun has produced energy for billions of years. Solar energy is the solar radiation that reaches the earth. It can be converted directly or indirectly into other forms of energy, such as heat and electricity.
What is solar energy?
Solar energy is the radiant energy (light or heat) that comes from the sun.Only a small amount of the sun's energy strikes the Earth, one part per two million. Even the one part is an enormous amount of energy.
How solar power works
Sunlight can be directly used to create electricity using solar cells. The solar cells are made using silicon, the same thing that makes up sand. Even though silicon is found almost everywhere, making a solar panel is a difficult and expensive process. The silicon is heated and melted at super high temperatures, and then molded into thin wafers. When sunlight strikes the solar cell, electrons are loosened and move toward a treated front surface, making an imbalance between the front and back. Electricity occurs when a connector, such as a wire, joins the negative and positive sides together. Read more in Chemist Paul Alivisatos explanation on how to generate electricity from sunlight.
History of solar energy
Solar energy has been used since the 7th century B.C. The sun's energy was used for heat, cooking, light, and to light fires.
Ancient Greeks and Romans designed architecture to use the sun’s capacity to light and heat indoor spaces. Read more.
Uses for solar energy
Solar energy can be converted directly and indirectly into other forms of energy, such as heat and electricity. It is used for heating water for domestic use, heating buildings, drying agricultural products, and generating electrical energy. Solar panels are used in some homes to convert the sun’s rays into electricity. Although not sold commercially,solar-powered vehicles can be found at demonstrations and educational sites globally. Solar cars use photovoltaic (PV) cells to convert the sun’s energydirectly into electrical energy. Solar energy is also absorbed by plants, land, and the ocean.
Demand for solar energy
There are significant challenges to overcome before solar power can be used on a wide-scale. Currently, less than 2% of the world’s electricity comes from renewable resources. The initial investment would be great, and it would require large amounts of physical space for photovoltaic (PV) cells panels.
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Solar power pros and cons
Pros
- Nonpolluting
- Most abundant energy source available
- Systems last 15–30 years
Con
- High initial investment
- Dependent on sunny weather
- Supplemental energy may be needed in low sunlight areas
- Requires large physical space for PV cell
panels
- Limited availability of polysilicon for panels
More solar resources
Solar Energy Solar Energy International
Provides links to energy web sites for kids
American Solar Energy Society
Offers general information on solar energy using text and resources for educators
International Solar Energy Society
Describes information on scientific and technical project for solar energy held by this society
Solar Energy Industries Association
Explains types of solar energy and includes a section on myths and facts
Solar Electricity Northeast Sustainable Energy Association (NESEA)
Explains two types of systems to create solar electricity with diagrams. Also addresses economic and environmental topics related to solar electricity.
Solar Water Heating Northeast Sustainable Energy Association (NESEA)
Discusses the basics of using solar power to heat water. |
