In modern world, question of energy sources is a very important one. Informational technologies and modern industry, medical and scientific equipment, communication tools – all are insatiable consumers of energy. Humanity needs for energy increase greatly with every new coming year, and old ways of producing energy that are based on fossil fuel combustion, can not satisfy growing needs of human race. Aside from low energy outcome, fuel combustion technologies are extremely harmful to the environment causing tremendous amounts of pollution.
In the face of global ecological disaster humanity needs new technologies that are both cheap, capable of producing continuously high amounts of energy and safe to the humanity and environment. Another important requirement from the new age energy sources is renewability – energy sources should be inexhaustible and constantly renewed in order to satisfy humankind’s lust for energy for a long period of time and avoid fast draining of these energy sources. Solar energy is one of those sources of energy that were ignored previously because of lacking technologies necessary to master endless stream of light and heat our planet receives every day.
Source of this energy is the Sun – star, that is technically nearest to the Earth. Ceaseless fusion processes that go on in the heart of every star cause constant streams of light radiation that are cast into the outer space. The Earth receives only an insignificant amount of this radiation, and large share of it is absorbed by the atmosphere, reflected back by the water masses, but even such small quantity of solar energy that reaches the surface of the Earth is still enough to support life on the Earth.
Just the tiny fraction of the Sun’s energy that hits the Earth (around a hundredth of a millionth of a percent) is enough to meet all our power needs many times over. In fact, every minute, enough energy arrives at the Earth to meet our demands for a whole year – if only we could harness it properly. ” (“Energy Resources: Solar power,” 2008). Excess energy that is invariantly lost to the ecological systems nowadays can be stored and used in any way humanity needs. Solar energy has the broad list of advantages in favor of its use. One of these advantages is its inexhaustibleness.
The Sun constantly emits radiation and the Earth constantly receives its cut of emitted energy. Solar radiation is accessible in almost any part of the Earth save polar regions during the polar nights. Another advantage of solar energy – this source of energy is renewable. Stocks of hydrogen which is the fuel for thermonuclear fusion processes in the core of the Sun are extremely large. Scientists predict that the Sun will exist in its current state for about five billions ? years, so it can be perceived as not just renewable but virtually inexhaustible source of energy.
Yet another advantage – solar energy is a sort of clear energy. There is no fossil fuel combustion, so no extra carbon dioxide is released into the atmosphere. There is also no pollution that may arise during the mining (coal) and transportation (oil spills in cases of oil tankers crashes) of fossil fuels to the power plants. There is no heat pollution which is common in nuclear power plants, and no risk of radioactive emissions in case of nuclear power plant equipment incorrect functioning. Solar energy is clear and safe for both the environment and the humankind.
Solar energy also can be accessed in indirect ways. One of these indirect effects of solar energy is the wind energy (“Solar Energy,” n. d. ). Rays of the sun heat certain regions of the Earth’s surface more intensively than other, and more heated regions warm up adjacent air masses. Thus conditions for circulation of air masses known as wind effects are created. Winds can be rather powerful and their energy can be captured by the windmills, thus using another amount of solar energy already absorbed by the ground.
Second indirect effect of solar energy that can be of use is biomass of the plants (“Solar Energy,” n. d. ). Plants use solar energy to synthesize organic substances of their bodies from non-organic components. Biomass of plants accumulated during the vegetation period can be used as direct (firewood) or indirect (biofuel production) source of energy. Direct capturing of solar energy can be performed in several ways. First one is the use of solar cells, also known as “photovoltaic”, “PV” or “photoelectric” cells (“Energy Resources: Solar power,” 2008).
These cells convert sunlight directly into electricity. The second way is use of water to absorb the heat of the sunlight (“Energy Resources: Solar power,” 2008). This technology is used broadly in everyday life to heat the water using heat of the sun instead of heat of burning gas. Third way of utilizing solar energy is solar furnace construction (“Energy Resources: Solar power,” 2008). Solar furnaces capture sunlight from rather broad area and concentrate it in the single point. Extremely high temperatures can be easily achieved using this technology.
Another interesting way of combined use of solar energy is solar towers construction. The core of idea is combination of large greenhouse heated by the rays of the sun and a tower of sufficient height. The principle of solar tower is rather simple: “the hot air from the greenhouse will rise up this tower, fast – and can drive turbines along the way” (“Energy Resources: Solar power,” 2008). Solar energy has its drawbacks though. Significant amounts of space required for building solar power station that will produce sufficient amounts of electricity.
Therefore solar power stations hardly can be of use to the countries that have no spare territories to use them as zones for capturing solar energy. Along with territory, solar power stations have to be constantly exposed to sunlight. Therefore solar power stations can function effectively only during daytime. In the night these power stations can’t work and hence they are of little use in the time of long nights. Solar power stations are also affected by weather. Clouds that cover the sky decrease performance of solar power station greatly.
Therefore these stations work their best in regions where constant intensive total insolation is high and clouds are rare guests. Some regions that fit under these requirements are African Sahara Desert (as well as the other large deserts) and Australia. Another major disadvantage of solar energy today is high cost of equipment and components required to build a solar power station: “Solar cells cost a great deal compared to the amount of electricity they’ll produce in their lifetime” (“Energy Resources: Solar power,” 2008). “The use of silicon crystals in the Photovoltaic cells makes it expensive.
First of all, silicon crystals are currently assembled manually. Secondly, silicon purification is difficult and a lot of silicon is wasted. In addition, the operation of silicon cells require a cooling system, because performance degrades at high temperatures” (“Solar Energy,” n. d. ). Although solar energy itself is a clear energy that generates neither wastes nor pollution, production of photovoltaic cells can be source of pollution of the environment, largely because of multistage purification of silicone for only highly purified silicone is good for photovoltaic cells production.
Yet last, but not the least disadvantage of solar power factories is the possibility to harm ecological systems of deserts where vast territories will be taken from to build the solar power station. This risk can not be left unmentioned and unassessed. Despite all difficulties and disadvantages mentioned solar energy has great potential as clean, safe and inexhaustble energy source though. Current technologies do not allow humanity to explore all the possibilities of environmental energy, but still scientists predict that “solar cells will become a significant source of energy by the end of the century” (“Solar Energy,” n. d. ).