Energy in layman’s language is the ability to do physical work; solar energy is, therefore, the ability to do physical work with the sun being the source. According to science, energy is neither created nor destroyed but it is transformable from one form to another; for instance potential energy, i.e. energy in its storable form can be easily converted to heat energy, electrical, light, and nuclear and kinetic energies. Kinetic energy is also known as the energy of moving objects. Sun according to science is the source of all energies at work on planet earth. The star sun which is the center of the galaxy Milky Way holds the earth and other planets in distinct orbits through heavy gravity which is further expounded scientifically through centripetal and centrifugal concepts. Planet earth is strategically positioned on the third orbit from the sun to be able to support life. This position is neither too far nor too near to the sun, hence ideal for the proliferation of life. All living things are dependent on the sun as the primary source of energy. A classical illustration of the transformation of solar energy through different forms in support of life on earth is; the synthesis of stored energy by plants using sunlight as the source, consumption of this stored energy in form of carbohydrates by animals, combustion of this stored energy by animals to generate heat and kinetic energies vital for sustenance of life on earth and transformation to other kinds of stored energies like crude oil, coal and manure with time through death and decomposition.
A man unlike other living things throughout history has been able to arrest this energy in its different forms, manipulated it to suit his service, and stored it in the most suitable forms for future utility. A simple example is cutting and preserving wood to use as a source of heat during the cold season. The use and handling of energy by man have evolved over time with changing demands of life. From direct sunlight to food in plants, wood, coal, oil leading to electricity and now nuclear energy. The application of energy in life by man is intense and diverse; beyond the scope in a single encyclopedia. Solar energy has befitted man from his medieval days to today. Its use as a mere source of light and warmth during daytime can be branded as an obvious nature’s supply which doesn’t warrant many words in this write-up. Of interest is man’s progressive effort overtime to arrest this solar energy, store it and later use it to do work. The very first documented arrest and use of solar energy by man was in drying foods stuffs, fabrics and bricks classical of ancient civilizations like Egypt and early Greece. Solar energy during these eras was used to preserve foods through primitive sun baking. Fish, meat, grain and dates preservation employed solar energy to dry excess water which would otherwise make them stale before the due date of planned consumption. Stone surfaces and metallic plates were used as solar energy arrestors to absorb required heat energy to dry these food stuffs. Solar energy was relied upon in bricks making and building of ancient cities like Babylon and Egypt (Daniels 92). Temperature controlled kilns were used to arrest solar energy for brick drying, wood drying and pottery works all employed in constructions.
Early documented arrest and improved use of solar energy were by Romans who used glass to tap it into their utility, they erected glass buildings to give plants best conditions the concept of modern greenhouse. The invention of neo-solar energy was made by Horace in 1776 where he used boiled ammonia for refrigeration. More developments were done by Edmund Becquerel 1836; He studied materials that turned solar energy into storable energy. In 1860’s Auguste Mouchout made a big development in solar energy technology by inventing a motor run by solar energy, he used this motor in refrigeration and successfully demonstrated that solar energy could be used to make ice. Auguste in his works also developed a solar ran steam engine. In 1876, Willoughby Smith discovered that selenium cells could be used to generate energy based on their sensitivity to solar energy. Charles Fritz in 1883 made a milestone in solar energy technology by converting solar energy to electrical energy. Between 1883 and today, there has been much improvement from Charles Fritz concepts by numerous other scientists leading to today’s fully evolved solar technology. Application of solar technologies today is very diverse and complex in scope, raging from agriculture, to research through lighting and electrical appliances to space science; solar technologies is unbeatable and holds the key solution to today and tomorrow’s energy crisis.
Conversion of solar energy to electrical energy is the most effective way of harnessing solar energy; it takes place on solar panels made up of photosensitive silicon cells also known as photovoltaic cells. What makes silicon a useful element in this technology is its semiconducting nature, i.e. given different conditions it can conduct or fail to conduct electricity. Sun light when it strikes on these photovoltaic cells, part of its energy is absorbed in the semi conducting material. This energy knocks loose electrons on semiconducting material causing them to flow freely. Photovoltaic cells have got an electric field that makes displaced electrons to flow in one direction. This flow of electrons generates a current otherwise known as electricity which is transferred through conducting metallic media to storage in batteries or to direct use like in light powered calculators. Other methods of harnessing of solar energies involve concentration of sun rays through converging mirrors on a common spot; to generate heat energy useful in heating appliances. Solar energy utility in green houses is direct; conditions are made perfect for the only useful light by plants to filter through into the green house (James 123). Another different application is in research where light engineers are able to split a band of sun rays to different colorful light waves useful in opera applications like in cameras. Solar energy enables humans to synthesize vitamin D, useful in formation of strong bones thus prevention of some skeletal malformations like rickets. It does this by triggering a sequence of enzymatic synthesis of vitamin D from the skin.
Benefits of solar energy today are innumerable, space science would be impossible without it, satellites, space ships and stations all tap from solar. There is no other kind of energy supply that can match solar energy in consistency and reliability in space science applications. Solar energy is being used today as an alternative source of electricity; it is being employed as the main source of street lighting in modern cities globally. Solar panels are being installed and used as a source of electricity in remote communities round the globe; who cannot access the central cable supplied electricity power; its use ranges from charging mobile phones, lighting homes, powering television sets, radios and computers. Solar energy has an advantage over conventional energy sources in that it is clean it produces zero emission; it’s affordable and renewable. It is available in almost all habitable corners of earth. With the right technologies, it can be used to fuel vehicles. It makes people independent in that one does not have to rely on conventional power supply companies for his electricity needs. Solar panels produce electricity silently, i.e. they don’t generate noise characteristic of power generators and rolling turbines. It offers a cheaper alternative in water heating than other electrical or coal powered water heaters. Solar energy is non obstructive, it reaches us through radiation unlike other conventional electrical energies which employ hazardous and obstructive heavy cabling for distribution. Solar energy is non discriminative, it reaches the haves and have-nots alike. Solar energy offers a promising solution to all future electricity needs; it’s worth more investing into than other non renewable sources.
A major drawback of solar energy is that its weather dependent, and that can only be harvested during the day. It does not perform well in cold and cloudy climates. It is seasonal in that its intensity of supply varies with varying seasons. Direct solar energy has been associated with some ailments like skin cancer. It is crude in that it combines different energies together; solar energy comes in both thermal and light energies. Sometimes this thermal energy works to destroy than to benefit man. A classical example is impromptu uncontainable wild fires caused by sun’s high thermal energy. Solar energy is unpredictable and fluctuating. This makes it very unreliable; one can not use it as a base to plan for some future energy needs. It requires high technologies to tap and use and store (Bolton 79). Solar energy is mostly feeble in intensity; it can not be used in heavy electrical appliances. Unlike other conventional energies, solar energy is hard to control or tame. It dictates that it cannot be turned off when not needed or when causing a hazard. Solar panels are left outside on building roofs or somewhere in open fields. Here they face security threats and can easily be stolen or vandalized. Solar energy can be said to be geo-selective in that it more in some parts of earth than others. It is so much within the tropics but very absent around the poles, discriminating against the Eskimos who inhabit these areas. Solar energy can be said to be the direct cause of climate modification, high temperatures near the earth surface caused by high thermal energies from the sun among other causes leads to global warming. Solar energy technology unlike other sources of energy has been studied for over a century consuming much resources and time in research; yet there has not been a milestone development in overcoming its major draw backs. Solar energy is too common, hence unlike nuclear energy no civilization can boast of controlling more of it than another. This lack of scarcity makes it to loose value in the eyes of investors.
Bolton, J. (1999). Solar power and fuels. New York. Penguin books.
James, C. (1998). Facts about solar energy. New York. Macmillan Publishers.
Daniels, F. (1990). Direct use of solar energy. Landon. Oxford university press.