Текст 1. The use of solar energy
One of the uses of solar energy is its transformation into electric energy. Photoelectric converters operate not only aboard space vehicles (космические корабли). They are used to supply hard-to-reach (трудно доступный) sites, for instance, light-houses (маяки), communication facilities (средства связи), etc. with electric power. Such installations can operate continuously for 20 years, and their capacity is up to 500 watts. They are reliable and do not need constantly handling by personal.
At present, mainly semiconductor silicon is used for the manufacture of photocells. Now the researchers have designed photocells on the basis of linking two materials in a single crystal-gallium arsenide and aluminum arsenide. They are most promising for the transformation of preliminary concentrated light since they continue to operate efficiently at temperature of over 200˚ C. Using heat that is released in photocells one can raise the efficiency up to 30%. Their use in solar power station will greatly cut the cost of the photoelectric method of energy transformation.
The problem of wider uses of renewable energy sources – solar, tidal and geothermal ones is of great local importance. So far (пока что) the practical use of solar energy is not very significant but the use of this energy can be profitable in many areas even now. Specialists designed water-heating installations for both seasonable and year-round operation. They have already built solar-powered homes and public buildings with hot water supply, heating and air-conditioning. Within the next few years experimental constructions will go on. After tests the best solutions will be used in standard designs.
The application of solar installations in agriculture has considerable effect. The experience in experimental solar-heating greenhouses (теплица) has shown that, as compared with ordinary greenhouses that receive heat from boiler rooms, the expenses on vegetable-growing are reduced by 60% due to fuel savings alone. Solar-powered installations for drying farm products were also tested successfully.
Текст 2. Renewable energy sources
In the future the energy of the sun, wind, sea and the heat of underground waters will be used on a large scale. These are the so-called “free” energy sources. They will be utilized only when they are more profitable than the traditional ones, because their exploitation is usually much more expensive than energy supply from large electric power stations which run on coal or nuclear fuel.
The utilization of the biomass – agricultural wastes and city runoff – can be found very effective: they can be employed in obtaining gas.
In addition it may happen that new energy sources will be discovered. What if, for example, the vacuum is a boundless ocean of matter in some specific state? Perhaps in the future man will discover some ways of getting energy from this matter? Or, for example, the undiscovered cosmic forces or the annihilation energy which arises from the fusion of matter and anti-matter.
Now this is fantasy which may become a reality. Unknown and undiscovered phenomena can be found more effective, than familiar ones.
Текст 3. Atomic energy
A man that tries to see a single atom is like a man trying to see a single drop of water in the sea. He will see the sea made of great many drops of water but he will not be able to see a single drop. Man has, however, learned the secret of the atom. He has learned to split atoms in order to get great quantity of energy. At present, coal is one of the most important fuels and our basic source of energy. It is quite possible that some day coal and other fuel may be replaced by atomic energy.
The nuclear reactor is one of the most reliable “furnaces” that produce atomic energy. When reactor produces energy it produces energy in the form of heat. In other words, when atoms split in the reactor heat is developed. Gas, water, melted metals and some other liquids circulate through the reactor to carry that heat away. The heat may be carried to pipes of the steam generator that contains water. The steam drives a turbine; the turbine in its turn drives an electric generator. So we see that a nuclear power-station is like any other power-station but the familiar coal-burning furnace is replaced by a nuclear one.