Solar energy is the sun’s rays, or solar radiation, that reaches the earth, which can then be converted into other forms of energy, such as heat and electricity. One of the first uses of converted solar energy was in the 1830’s, when the British astronomer, John Herschel, used a solar thermal collector box to cook food during an expedition to Africa.
Solar energy can be converted to electricity in two ways. Photovoltaic devices or “solar cells” change sunlight directly into electricity. Such systems are often used in remote locations that are not connected to the electric grid. They are also used to power watches, calculators, and lighted road signs. There are also solar power plants which indirectly generate electricity when the heat from solar thermal collectors is used to heat a fluid which produces steam that is used to power generator.
Advantages of solar energy are it is free, its supplies are unlimited, and using solar energy produces no air or water pollution. However it may indirectly have a harmful impact on the environment. For example, manufacturing the photovoltaic cells consumes silicon and produces some waste products, and large solar thermal farms can also harm desert ecosystems if not properly managed.
Some other disadvantages of solar energy as an energy source are that the amount of sunlight that arrives at the earth's surface is not constant, depending on location, time of day, time of year, and weather conditions. Further, solar energy from the sun is spread over the whole earth’s surface and cannot be directed into a specific place, it doesn't deliver large amounts of energy to any one place at any one time. Thus a large surface area is required to collect the energy at a useful rate.
Solar energy can be converted to electricity in two ways. Photovoltaic devices or “solar cells” change sunlight directly into electricity. Such systems are often used in remote locations that are not connected to the electric grid. They are also used to power watches, calculators, and lighted road signs. There are also solar power plants which indirectly generate electricity when the heat from solar thermal collectors is used to heat a fluid which produces steam that is used to power generator.
Advantages of solar energy are it is free, its supplies are unlimited, and using solar energy produces no air or water pollution. However it may indirectly have a harmful impact on the environment. For example, manufacturing the photovoltaic cells consumes silicon and produces some waste products, and large solar thermal farms can also harm desert ecosystems if not properly managed.
Some other disadvantages of solar energy as an energy source are that the amount of sunlight that arrives at the earth's surface is not constant, depending on location, time of day, time of year, and weather conditions. Further, solar energy from the sun is spread over the whole earth’s surface and cannot be directed into a specific place, it doesn't deliver large amounts of energy to any one place at any one time. Thus a large surface area is required to collect the energy at a useful rate.