Solar energy
Solar energy is quite simply the energy produced directly by the sun and collected elsewhere, normally the Earth. According to Laird “The sun creates its energy through a thermonuclear process that converts about 650,000,000 tons of hydrogen to helium every second. The process creates heat and electromagnetic radiation. The heat remains in the sun and is instrumental in maintaining the thermonuclear reaction. The electromagnetic radiation (including visible light, infra-red light, and ultra-violet radiation) streams out into space in all directions.” (Laird, pp. 4-5) Only a very small fraction of the total radiation produced reaches the Earth. The radiation that does reach the Earth is the indirect source of nearly every type of energy used today. The exceptions are geothermal energy, and nuclear fission and fusion. Even fossil fuels owe their origins to the sun; they were once living plants and animals whose life was dependent upon the sun. Much of the world's required energy can be supplied directly by solar power.
According to Moore “Sunlight can be used in two ways to generate energy; direct heating and photovoltaic electrical generation. Using current technology it takes approximately 40 square meters of collector area to provide enough solar energy from direct solar heating for the all the energy needs of an individual each day. This is assuming the current efficiency of passive solar collectors which ranges between 20% to 80% and eight hours of sunshine in a temperate zone. While direct sunlight can be used to create heat, it is of limited value in electrical generation. Thought solar furnaces can be designed to focus light, and create steam to generate electricity; currently direct sunlight applications have limited potential in electrical generation.” (Moore, pp. 6-8) Photovoltaic generation, or direct conversion of sunlight into electricity, has only a 7% to 11% efficiency range, yet even at these low rates of efficiency this use of sunlight can be a competitive form of power generation................
