What is Solar Energy?
Solar energy is energy that comes from the sun. Every day the sun radiates an enormous amount of energy. The sun radiates more energy in one second than people have used since the beginning of time. All this energy comes from within the sun itself. Like other stars, the sun is a big gas ball made up mostly of hydrogen and helium. The sun generates energy in its core in a process called nuclear fusion. Only a small portion of the energy radiated by the sun into space strikes the earth, one part in two billion. Yet this amount of energy is enormous. Every day enough energy strikes to supply one nation’s energy needs for years! About 15 percent of the sun’s energy that hits the earth is reflected back into space. Another 30 percent is used to evaporate water, which, lifted into the atmosphere, produces rainfall. Plants, the land, and the oceans also absorb solar energy. The rest could be used to supply our needs.
ADVANTAGES AND DISADVANTAGES OF SOLAR ENERGY
Solar energy makes use of a renewable natural resource that is readily available.
Solar power used by itself creates no carbon dioxide or other toxic emissions.
Use of solar thermal power to heat water or generate electricity will help reduce the Territory’s complete dependence on fossil fuels.
Solar water heaters are an established technology, readily available on the commercial market, and simple enough to build, install and maintain by yourself.
The production of electricity by the photovoltaic process is quiet and produces no toxic fumes. PV cells generate direct-current electricity that can be stored in batteries and used in a wide range of voltages depending on the configuration of the battery bank.
Although most electric appliances operate on alternating current, an increasing number of appliances using direct current are now available.
Where these are not practical, PV-generated direct current can be changed into alternating current by use of devices called inverters.
Solar thermal systems are not cost-effective in areas that have long periods of cloudy weather or short daylight hours.
The arrays of collecting devices for large systems cover extensive land areas.
Solar thermal systems only work with sunshine and do not operate at night or in inclement weather.
Storage of hot water for domestic or commercial use is simple, using insulated tanks, but storage of fluids at the higher temperatures needed for electrical generation, or storage of electricity itself, needs further technical development.
Photovoltaic-produced electricity is presently more expensive than power supplied by utilities.
Batteries need periodic maintenance and replacement. High voltage direct-current electricity can pose safety hazards to inadequately trained home operators or utility personnel.