Introduction
There is a figurative expression, that we live in the era of the three «e»: economy, energy, and ecology. In this case energy as a science and a way of thinking attracts more and more attention of mankind.
Problems of power engineering
Energy is the branch of production, which is developing very rapidly. If the number of population in the context of modern demographic explosion is doubled for 40-50 years, the production and consumption of energy, it goes through every 12-15 years. When the ratio of growth rates of population and power engineering, power availability rapidly growing not only in aggregate terms, but also in per capita terms. There is no reason to expect that the rate of energy production and consumption in the short term would substantially change (some slowdown them in the industrialized countries is compensated by growth of energy potential of the countries of the third world), so it is important to get answers to the following questions:
• what is the impact on the biosphere and some of its elements the basic forms of modern (heat, water, nuclear) energy have and how will change the ratio of these species in the energy balance in the short and long term;
• is it possible to reduce the negative impact on the environment modern (traditional) methods of obtaining and use of energy;
• what are the opportunities for the production of energy at the expense of alternative (non-traditional) resources, such as solar, wind, thermal waters and other sources, which are related to the inexhaustible and environmentally friendly.
At present, energy needs are provided mainly at the expense of the three types of energy: fossil fuel, water and atomic nucleus. The energy of the water and the atomic energy used by people after its transformation into electric energy. At the same time a significant amount of energy contained in organic fuel is used in the form of heat and only part of it is transformed into electricity. However, and in that and in other case of a release of energy from fossil fuels is associated with its combustion and, consequently, with the receipt of combustion products into the environment.
Ecological problems of heat energy
Due to the combustion of fuel (including wood and other bio-resources) currently produces about 90% of the energy. The share of thermal sources is reduced to 80-85% in the production of electricity. While in industrialized countries oil and oil products are mainly used for the needs of transport. For example, in the USA oil in the total energy balance of the country was 44%, and in obtaining electricity – only 3%. For coal is characterized by the opposite pattern: with 22% in the total energy balance, it is essential in obtaining electricity – 52%). In China, the share of coal in obtaining electricity close to 75%, at the same time in Russia the predominant source of energy is natural gas (is about 40%), and coal accounts for only 18% of the received energy, oil’s share does not exceed 10%. On a global scale hydro-power resources provide about 5-6% of electric power (in Russia 20,5%), atomic energy gives 17-18% of the electric power. In Russia the share of it close to 12%, and in some countries it is the dominant in the energy balance (France – 74%, Belgium – 61%, Sweden – 45%). Fuel combustion is not only the main source of energy, but also a major supplier of contaminants into the environment. The thermal power stations in the highest degree «responsible» for increasing the greenhouse effect and fallout of acid precipitation. They, together with transport, supply in the atmosphere of a major share of anthropogenic carbon (mostly in the form of CO2), about 50% of sulphur dioxide, 35% – nitrogen oxides, and about 35% of dust. There is evidence that the thermal power plants in 2-4 times more polluted environment radioactive substances, than nuclear power plant of the same capacity. Emissions from TPSs contains a significant amount of metals and their compounds. When measured against fatal doses of the annual emissions of the TPSs with a capacity of 1 million kW contains aluminum and its compounds above 100 million doses, of iron – 400 million doses, of magnesium – 1.5 million doses. Lethal effect of these pollutants not only occur because they fall into organisms in small quantities. This, however, does not exclude their negative impact through water, soil and other parts of ecosystems. We can assume that the thermal energy has a negative impact on virtually all elements of the environment, as well as on a person, other organisms and their communities. Also the influence of the energy sector on the environment and its inhabitants in a greater measure depends on the type of used energy sources (of fuel). The most pure fuel is natural gas, followed by oil (fuel oil), stone coal, brown coal, shale, and peat. At present a significant share of electricity is produced at the expense of relatively clean types of fuel (gas, oil), but is a natural tendency of reduction of their share. According to forecasts, these energy carriers will lose its leading role already in the first quarter of the XXI century. There is a possibility of a significant increase in world energy balance use of coal. It is estimated that coal reserves are such that they can provide the world’s energy needs for 200-300 years. Possible production of coal given the proven and probable reserves, estimated at more than 7 trillion tons. While more than 1/3 of the world’s reserves of coal are located on the territory of Russia. Therefore, it is logical to expect an increase in the share of coal and products of their processing (e.g., natural gas) in the procurement of energy and, consequently, in the contamination of the environment. Coals contain from 0.2 up to tens of percent of sulfur mostly in the form of pyrite, sulfate, oxide iron and plaster. Available methods of capture of sulphur from combustion of fuel is not always used because of the cost and complexity. So a significant number of it is delivered and, apparently, will be supplied in the nearest future in the environment. Serious environmental problems associated with solid waste TPSs – ash and slag. Although ash in the bulk of the catches of different filters, all the same in the atmosphere in the form of emission TPSs are received every year about 250 million tons of fine-dispersed aerosols. This aerosols are able to significantly change the balance of solar radiation at the earth’s surface. They are the nuclei of condensation for water vapor and the formation of precipitation; falling into the respiratory system of humans and other organisms that can cause a variety of respiratory diseases. Emissions of TPSs to be a significant source of such a strong carcinogenic substance, as benzopyrene. With its effects associated increase of oncological diseases. In the emissions of coal-fired TPPs also contains oxides of silicon and aluminium. These abrasives can destroy lung tissue and cause such a disease, like silicosis, which earlier sick miners. Now the cases of silicosis are registered among children living near coal-fired thermal power plants. A serious problem near the thermal power plant is storage of ash and donkeys. This requires considerable territory, which for a long time of not being used, but also are centres of accumulation of heavy metals and of increased radioactivity. There are data, that if all of today’s power was based on coal, the emissions of CO, amounted to 20 billion tons per year (now they are close to 6 billion tons per year). This is the limit beyond which predicted such climate change, which will cause catastrophic consequences for the biosphere. TPS – an important source of heated water, which are used here as a cooling agent. These waters are frequently caught in the rivers and other water bodies, causing their thermal pollution and its accompanying chain natural reaction (reproduction of algae, loss of oxygen, the death of hydrobionts, the transformation of the typical aquatic ecosystems in the swamp, etc.).
Ecological problems of hydro-power
One of the most important impacts of hydro-power associated with the disposal of large areas of fertile (floodplain) lands under water reservoirs. In Russia, where due to the use of water resources is no more than 20% of electric energy, the construction of HPPs flooded not less than 6 million hectares of lands. In their place destroyed by natural ecosystems. Large areas of land near reservoirs are experiencing flooding as a result of increase of a level of subsoil waters. These lands, as a rule, are transferred into the category of wetlands. In plain terms underflooded of the earth can be 10% or more from the flooded. The destruction of the land and of their own ecosystems can also occur as a result of their destruction of water (abrasion) in the creation of the coastline. Abrasion processes are usually continue for decades, have the effect of processing of large masses of soils, water pollution, silting up of reservoirs. Thus, with the construction of reservoirs caused the breakdown of the hydrological regime of the rivers, their inherent ecosystems and species composition of aquatic organisms. So, Volga practically all over (from the source to the Volgograd) turned into a continuous system of reservoirs. Deterioration of the quality of water in the reservoirs happens for various reasons. In them dramatically increases the amount of organic substances at the expense of the gone under water ecosystems (wood, other plant residues, soil humus, etc.), and as a result of their savings as a result of the slow water exchange. It is a kind of settling tanks and batteries substances coming from watersheds. In the reservoirs of sharply increased heating of the water, which intensifies their loss of oxygen and other processes posed by thermal pollution. The latter, together with the accumulation of biogenic substances, creates the conditions for the overgrowing of water reservoirs and intensive development of algae, including toxic blue-green (cyans). For these reasons, and also because of the slow of office of water sharply reduced their ability to self-purification. Deterioration of water quality leads to the death of many of its inhabitants. Increased incidence of fish schools, especially the defeat of lungs. Reduced taste of the inhabitants of the aquatic environment. Violated the migration routes of fish, there is a destruction of grassland, spawning grounds and etc. Volga largely lost its importance as spawning grounds for sturgeon of the Caspian sea after the construction on her cascade of HPS. Ultimately blocked reservoirs in the river system from the transit turn into transit – accumulative one. In addition to nutrients, here accumulate heavy metals, radioactive elements and many of the pesticides to the long period of life. The products of the accumulation of doing problematic possibility of use of the territories occupied by reservoirs, after their liquidation. There is evidence that as a result of sedimentation plains of the reservoir lose its value as energy objects in 50-100 years after their construction. For example, it is estimated that the great Aswan dam, built on the Nile in the 60-ies, will be half silt by 2025. Despite the relative cheapness of energy, which is obtained at the expense of water resources, their share in the energy balance gradually decreases. This is due to the exhaustion of the cheap resources, as well as with a large territorial capacity of lowland reservoirs. It is believed that in the future world energy production by hydro power plants will not exceed 5% of the total. Reservoirs have a marked influence on atmospheric processes. For example, in the dry lands (arid) areas evaporation from the surface of the reservoir exceeds evaporation with equal land surface in dozens of times. Only with cascade the Volga-Kamsk reservoir annually evaporates about 6 km3. It is about 2-3 annual water consumption norms Moscow. With increased evaporation due decrease in air temperature, the increase in the vague phenomena. The difference of thermal balances of reservoirs and adjacent land causes formation of local winds type breezes. These, as well as other phenomena are a consequence of the change of ecosystems (not always positive), change in the weather. In a number of cases in the area of water reservoirs it is necessary to change the direction of the agriculture. For example, in the southern regions of our country some of the heat-loving cultures (melons) do not have time to ripen, increases the incidence of plants, worsens the quality of the products. Costs in hydraulic engineering for the environment is considerably less in the mountainous areas, where the reservoirs are usually small in area. However, in the earthquake-prone mountainous areas of the reservoir may provoke an earthquake. An increase in the probability of landslide phenomena and likelihood of disasters as a result of the possible destruction of dams. So, in 1960 in India (state of Gujarat) as a result of breaking of the dam waters rushed 15 thousands of lives of people.
Ecological problems of nuclear power
Nuclear energy until recently was considered as the most promising. This is due to the relatively large stocks of nuclear fuel, as well as with the non-destructive impact on the environment. The advantage is also a possibility of construction of NPPs, not attached to the fields of resources, because of their transportation does not require significant costs in connection with the small volumes. It is enough to note that 0.5 kg of nuclear fuel allows you to receive as much energy as burning of 1000 tons of coal. Until the mid of 1980s humanity has seen one of the outputs of the energy impasse in a nuclear power industry. Only in the 20 years (since the mid of 1960s to mid of 1980s) the global share of energy generated from nuclear power, has increased from virtually zero values of up to 15-17 %, and in some countries it has become prevalent. No other type of energy has had such growth rates. Until recently, the main environmental problems of NPSs associated with the disposal of spent fuel, as well as with the liquidation of the nuclear power plant after the end of the permissible operating life. There is evidence that the value of such liquidation works is from 1/6 to 1/3 of the value of the NPSs. During normal operation of the nuclear power plant emissions of radioactive elements in the environment are insignificant. They are on average 2 – 4 times less, than from TPPs of equal power. By May of 1986 400 units, working in the world and giving more than 17 % of the electric power, increased natural background radioactivity not more than 0. 02 %. Before the Chernobyl catastrophe in our country no industry had a lower level of industrial injuries, than NPSs. For 30 years before the tragedy in case of accidents, and so on irradiation reasons, killing 17 people. After 1986 the main ecological danger NPSs has become associated with the possibility of accidents. Although the probability of it in modern nuclear power plants and small, but it is not ruled out. The largest accidents of such a plan refers happened on the fourth unit of the Chernobyl nuclear power plant. According to various estimates, the total release of fission products from those of the reactor ranged from 3.5% (63 kg) and 28 % (50 tones). For comparison, the bomb dropped on Hiroshima, gave only 740 g of radioactive substance. As a result of the accident at the Chernobyl nuclear power plant radioactive contamination was a territory within a radius of more than 2 thousand km, covering more than 20 states. Within the former USSR suffered 11 areas, where are 17 million people. The total area of contaminated territories exceeds 8 million hectares (or 80 thousands km3 ). In Russia, the most significantly affected Bryansk, Kaluga, Tula and Orel regions. Spots of pollution are available in the Belgorod, Ryazan, Smolensk, Leningrad and other areas. As a result of the accident killed 31 people and more than 200 people received doses of radiation, leading to radiation sickness. 115 thousand people were evacuated from the most dangerous (30 km) area immediately after the accident. The number of victims and the number of evacuees increases, expanding the zone of pollution as a result of movement of radioactive substances wind, when the fires, transport and etc. The consequences of failure will affect the life of several generations. After the accident at the Chernobyl NPP some countries have adopted a decision about a full ban on the construction of a NPSs. Among them Sweden, Italy, Brazil, Mexico. Sweden, in addition, has announced its intention to remove all existing reactors (12), although they gave about 45% of all the country’s electricity. Abruptly slowed down the pace of development of this type of energy in other countries. Take measures to strengthen the protection against accidents existing, under construction and planned to build a nuclear power plant. However, mankind is aware that without nuclear energy at the present stage of development is not enough. Construction and putting into operation of the new NPP is gradually increasing. At present in the world there are more than 500 nuclear reactors. About 100 reactors is in the stage of construction. On the territory of Russia is located 9 nuclear power plant, including 29 reactors. 22 of them reactor falls on the most populated European part of the country. 11 reactors refers to the type of RBMK reactors. At the Chernobyl nuclear power plant there was a destruction of the reactor of this type. Many reactors (by number of more than NPPs) is installed on submarines, icebreakers, and even in outer space objects. In the process of nuclear reactions burn only 0, 5 – 1,5% of nuclear fuel. Nuclear reactor with a capacity of 1000 MW for the year of work throws out about 60 tons of radioactive waste. Part of them is subjected to processing, and the bulk requires burial. The technology of Disposal is quite complicated and expensive. The spent fuel is usually overloaded in the pools of exposures, where for a few years significantly reduced radioactivity and heat dissipation. Burial is usually carried out at depths of not less than 500 – 600 away. The latter are located from each other at a distance, to eliminate the possibility of nuclear reactions. The inevitable result of the work of nuclear power plants – thermal pollution. Per unit of generated energy here it is in 2 – 2, 5 times more, than at thermal power plants, where significantly more heat is discharged in the atmosphere. Elaboration of 1 million kW of electricity at thermal power plants gives 1. 5 km3, heated water, the nuclear power plant of the same capacity volume of heated water reaches 3-3,5 km3. A consequence of the large losses of heat at the power plant is more low efficiency compared to thermal power plants. On the latter, he is equal to 35 %, and nuclear – only 30 – 31 %. In general, the following can be mentioned the impact of NPPs on the environment:
• the destruction of ecosystems and their components (soils, water-bearing structures and etc.) in places of extraction of ore (especially when I open method); • withdrawal of lands under construction of the nuclear power plant. Especially significant area alienated for the construction of facilities for the supply, heat and cooling of the heated water. For the power plant with the capacity of 1000 MW is required pond-cooler area of about 800 – 900 ha. Ponds can be replaced with the giant cooling towers with a diameter at the base of 100 – 120 m and a height equal to 40-storey building;
• withdrawal of large volumes of water from various sources and discharge of heated water. If the water fall in the rivers and other sources, in them there is a loss of oxygen, increases the likelihood of flowering, increasing phenomenon of thermal stress in aquatic organisms;
• not possible radioactive contamination of the atmosphere, water and soil in the process of production and transportation of raw materials, as well as in the operation of nuclear power plants, storage and processing of wastes, their graves.
Some ways of solution of the problems of modern power engineering
No doubt, that in the short term thermal energy will remain dominant in the energy balance of the world and individual countries. The probability of increasing the share of coal and other types of less clean fuels in energy production. In this connection let us consider some of the ways and methods of their use, allowing to significantly reduce the negative impact on the environment. These methods are based mainly on the improvement of the technologies of the fuel and capture of hazardous waste. They include the following:
1) The use and improvement of water treatment devices. At the present time in many TPSs are captured mainly solid emissions with the help of various types of filters. One of the most aggressive polluter – sulphurous anhydride on many TESs is not captured or is trapped in a limited number. At the same time, there is a thermal power plants (USA, Japan), which is almost complete cleaning of the pollutant, as well as from oxides of nitrogen and other harmful pollutants. For this we use special desulphurization (for capturing dioxide and sulfur trioxide) and denitrification (for capturing nitrogen oxides) installation. The most widely capture of sulphur and nitrogen oxides is carried out by means of the bandwidth of the flue gases through the ammonia solution. The end-products of this process are ammonium nitrate, used as mineral fertilizer, or solution of sodium sulphite (raw materials for the chemical industry). Such an installation is caught up to 96% of sulfur oxides and more than 80% of nitrogen oxides. There are other methods of treatment of these gases.
2) Reduction of supply of sulphur compounds in the atmosphere by means of a preliminary desulphurization coal and other fuels (oil, gas, shale oil) chemical or physical methods. These methods manage to extract fuel from 50 to 70 % of sulfur up to the moment of its burning.
3) Big and real possibilities of reduction or stabilization of pollutants in the environment are connected with power savings. Most of such opportunities for Russia at the expense of reducing the energy intensity of the received goods. For example, in the United States per unit of the obtained product was spent on the average in 2 times less energy than in the former USSR. In Japan such expense was reduced by three times. No less real energy savings due to reduction of metal products, improvement of their quality and to increase life expectancy of the products. Promising energy saving at the expense of transition to knowledge-intensive technologies associated with the use of computer and other devices.
4) Not less significant opportunities to save energy in the home and the workplace through improved insulation of buildings. Real cost of energy gives the replacement of incandescent lamps with an efficiency of about 5 % of fluorescent, efficiency of which is several times higher. It is extremely wasteful use of electric energy for heat. It is important to note, that the reception of the electric power at thermal power plants is associated with the loss of approximately 60 – 65 % of thermal energy, and nuclear – not less than 70 % of the energy. Energy is lost also during its transmission over the wires at a distance. Therefore, direct fuel combustion to produce heat, especially gas, much better than through its transformation into electricity, and then again in the heat.
5) Significantly improved fuel efficiency when it is used instead of the TPS at the CHS plant. In the latter case, the objects of obtaining energy are close to the places of its consumption and thereby reduces the loss associated with the transfer of the distance. Along with the electricity at thermoelectric heat is used, which is captured cooling agents. This considerably decreases the probability of thermal pollution of the aquatic environment. The most economical way of reception of energy at smaller installations type TPS directly in the buildings. In this case the losses of heat and electric energy are reduced to a minimum. Such methods in individual countries are being increasingly used.
Alternative sources of energy
The major modern sources of energy (especially fossil fuels) can be considered as a means of solving energy problems in the near-term outlook. This is due to their exhaustion and the inevitable pollution of the environment. In this connection it is important to get acquainted with the possibilities of the use of new sources of energy, which would replace the existing ones. These sources include solar, wind, water, thermonuclear synthesis, and other sources.
The sun as a source of heat energy
It is practically inexhaustible source of energy. You can use it directly (through capture the technical equipment) or indirectly through the products of photosynthesis, water circulation, the movement of air masses, and other processes that are driven by solar phenomena. The use of solar heat is the most simple and cheap way of solving the individual energy problems. It is estimated that in the United States for space heating and hot water supply consumes about 25 % of the country’s energy. In the Nordic countries, including in Russia, this proportion is much higher. Meanwhile, a significant proportion of heat, necessary for these purposes may be obtained by capture the energy of sunlight. These opportunities is the greater, the more direct solar radiation is brought to the surface of the earth. The most common capture of solar energy by means of various types of collectors. In its simplest form it is a dark color of the surface for trapping heat and equipment for its accumulation and retention. Both units can represent a single whole. Collectors are placed in a bowl, which operates on the principle of a greenhouse. There are also devices for reduction of energy dissipation (good insulation) and it leads, for example, the flow of air or water. Even more simple heating systems of passive type. The circulation of the heat-here is the result of convection currents: hot air or water rise up and take their place more chilled heat carriers. An example of such a system can provide a room with large Windows overlooking to the sun, and good insulation properties of the material, capable of continuously retain heat. To reduce the overheating of the day and the heat of the night are used drapes, blinds, canopies and other protective devices. In this case, the problem of the most efficient use of solar energy could be solved through proper design of buildings. A rise in the cost of construction is blocked by the effect of the use of cheap and clean energy. According to a study in the United States (for example, in California there are structures that even the passive type of accumulation of sunlight allow you to save up to 75 % of energy costs, the additional construction costs only a 5-10%. In Cyprus in 90 % of the houses, many hotels and apartment houses of the problem of heating and hot water supply are solved at the expense of solar water heaters. In Israel the share of dwellings provided solar energy, is close to 65 %. In other countries the targeted use of the solar energy is not yet great, but intensively to increase production of various kinds of solar collectors. In the United States there are thousands of such systems, although they provide while only 0. 5 % of the hot water supply. Very simple devices use sometimes in greenhouses or other structures. For greater accumulation of heat in the solar time of the day in such areas provide material with a large surface area and good heat capacity. This can be stones, coarse sand, water, gravel, metal, etc. During the day they accumulate heat, and at night gradually give it. These devices are widely used in greenhouses of the South of Russia, in Kazakhstan, Central Asia and other sun-rich areas.
The sun as a source of electric energy
The transformation of a solar energy in electric possible through the use of solar cells, in which solar energy is induced into electric current without any additional devices. Although the efficiency of such devices is small, but they are beneficial to slow expendability due to the absence of any moving parts. The main difficulties of the application of solar cells is related to their high cost and occupation of large areas for placement. The problem to some extent solved by replacing metal photoconverter energy elastic synthetic, use of roof and walls of houses for the accommodation of batteries, carrying out the converters in outer space, etc. In those cases when you want to receive a small amount of energy, the use of solar cells currently economically expedient. V. Nebel as examples of such use of the calls calculators, telephones, televisions, air conditioners, lighthouses, buoys, small irrigation systems, etc. In countries with a large amount of solar radiation available projects complete electrification of certain branches of the economy, such as agriculture, at the expense of solar energy. Obtained in this way energy, especially for its high ecological compatibility, the value turns out to be more profitable than the energy produced by traditional methods. Solar station bribe is also the possibility to quickly input in operation and build their capacity in the process of operation of a simple merger of additional solar cell batteries. In California built heliostation, the capacity of which is sufficient to provide electricity 2400 homes. The second way of transformation of a solar energy in electric is connected with the transformation of water to steam, which drives the turbine generators. In these cases, for accumulating energy the most frequently used energy tower with a large number of lenses that concentrate the sun’s rays, as well as special solar ponds. The essence of the latter is that they consist of two layers: the bottom with a high concentration of salts and upper presented transparent fresh water. The role of the material of the accumulating energy, performs a salt solution. The heated water is used for heating or vaporize the liquid, boiling at low temperatures. Solar energy, in some cases, promising also to get out of the water to hydrogen, which is called «the fuel of the future». The decomposition of the water and the release of hydrogen is in the process of bandwidth between the electrodes of the electric current produced by helioplants. Disadvantages of such facilities as related to low efficiency (the energy contained in hydrogen, only 20 % higher than that spent on electrolysis of water) and high Flammability of hydrogen, as well as its diffusion through the storage capacity.
Wind as an energy source
The wind, like water, are the most ancient sources of energy. In several centuries, these sources were used as a mechanical mills, power-saw benches, in systems of water supply to the places of consumption, etc. They are used for reception of electric energy, although the share of wind in this respect remained extremely low. Interest in the use of wind for electricity generation perked up in recent years. To the present time tested wind engines of different capacity, up to the giant. Conclusions are made that in areas with intensive movement of air wind-power plants may well provide the energy to local needs. Justified by the use of wind turbines for the maintenance of separate objects (houses, not a power-hungry, productions, etc.). However, it was obvious that the giant wind-power plants still do not justify themselves as the result of the high cost structures, strong vibrations, noise, quick exit from the system. More economical complexes of small wind turbines, integrated in one system. In the United States built a wind power plant on the basis of integration of a large number of small wind turbines with a capacity of about 1,500 MW (about 1.5 NPSs). Wide work is underway on the use of wind power in Canada, the Netherlands, Denmark, Sweden, Germany and other countries. In addition inexhaustible resource and high ecological compatibility of the production, the advantages of wind turbines include low cost received on them energy. She’s here in 2-3 times below, than at thermal and nuclear power plants.
Possibility of use of non-conventional water resources
Water resources continue to be an important potential source of energy provided the use of more environmentally friendly than modern methods of its receipt. For example, extremely insufficiently used the energy resources of the medium and small rivers (the length from 10 to 200 km). Only in Russia of such rivers there are more than 150 thousand. In the past, it is small and medium-sized rivers were the most important source of energy production. Small dams on the rivers is not so much the break, how many optimize the hydrological regime of the rivers and adjacent territories. They can be considered as an example of environmentally caused by the use of natural resources, soft intervention in natural processes. Reservoir, created on the small rivers, usually do not go beyond the limits of channels. Such reservoirs eliminate the fluctuations of the water in the rivers and stabilize the level of groundwater under the adjacent floodplain lands. This favorably affects the productivity and sustainability of marine and floodplain ecosystems. There are calculations that the small and medium-sized rivers can be received not less energy, than it is produced on the modern large-scale hydro. At the present time there is the turbines, which allow to receive the energy of using the natural flow of the rivers, without building dams. Such turbines are easy to install on rivers and if necessary move to other places. Although the cost received in these installations of energy is much higher, than on large scale hydro stations, thermal and nuclear stations, but high ecological makes it advisable to obtain it.
The energy resources of the sea, ocean and thermal waters
Large energy resources have masses of water of the seas and oceans. To him belongs the energy of tides, ocean currents, as well as gradients of temperatures at various depths. At the present time, this energy is used in extremely small quantities because of the high cost of obtaining. This does not mean, however, that in the future its share in the energy balance will not rise. In the world as long as there are two-three tidal power plant. In Russia the possibility of a tidal energy are significant in the White Sea. However, in addition to the high cost of energy, power plant of this type cannot be attributed to hi-tech. When the construction of dams overlap bays that dramatically alters the ecological factors and conditions of living organisms. In oceanic waters to get the power you can use the difference of temperatures at various depths. In the warm currents, for example in Gulf stream, they reach up to 20 degrees C. In the basis of the principle is the application of liquid, boiling and condensing with the small difference of temperatures. Warm water surface layers is used for transformation of liquid into steam, which spins a turbine, cold-depth weight – for steam condensation in the liquid. Difficulties are connected with the awkwardness of the structures and their expensiveness. Installation of this type are still at the stage of testing (e.g., in the United States). Incomparably more real possibilities of the use of geothermal resources. In this case, the heat source is warmed up water contained in the bowels of the earth. In some areas, the water flow to the surface in the form of geysers (for example, in Kamchatka)! Geothermal energy can be used both in the form of heat, as well as for obtaining electricity. There are also experiments on the use of heat contained in the solid structures of the earth’s crust. The heat from the mineral is extracted by pumping water, which is then used in the same way as other thermal water. Already at the present time some of the city or of the enterprise are provided with the energy of geothermal waters. This applies, in particular, to the capital of Iceland, Reykjavik. In the early 1980s in the world was on geothermal power plants around 5000 MW of electricity (approximately 5 nuclear power stations). In Russia the significant resources of geothermal waters are available in Kamchatka, but they are used while in a small volume. In the former USSR at the expense of the resources produced only about 20 MW of electricity.
Thermonuclear energy
Modern nuclear energy is based on splitting the nuclei of atoms in two more light with the release of energy in proportion to weight loss. Source of energy and of the products of decomposition are radioactive elements. Related to the main environmental problems of nuclear power. An even greater amount of energy is released in the process of nuclear fusion, in which two nuclei are fused into one of the more difficult, but also with the loss of mass and energy release. The original items for the synthesis of hydrogen is, the end – helium. Both elements have no negative impact on the environment and are virtually inexhaustible. The result of nuclear fusion is the energy of the sun. Man this process is modeled in explosions of hydrogen bombs. The challenge is how to nuclear fusion to make manageable, and its energy use purposefully. The main difficulty lies in the fact that nuclear fusion is possible under very high pressures and temperatures of around 100 million Degrees. There are no materials from which you can make reactors for the implementation of the over high-temperature (thermonuclear) reactions. Any material when it melts and evaporates. The scientists went on the way of search of opportunities of the implementation of the reactions in the environment, not able to evaporation. To do this, at the present time tested two ways. One of them is based on hold hydrogen in a strong magnetic field. Installation of this type received the name of the TOCHAMAC (Toroidal chamber with magnetic field). This camera is designed in the Institute of Kurchatov. The second way involves the use of laser beams at the expense of which is ensured by obtaining the desired temperature and in the places of concentration of which is served hydrogen. In spite of some positive results in the implementation of controlled nuclear fusion, expressed the opinion that in the nearest future it is unlikely to be used to solve the energy and environmental problems. This is due to the unresolved status of many of the issues and the necessity of the colossal costs of further experimental, and the more industrial development.
Conclusion
In conclusion, it can be concluded that the present level of knowledge, and also available and are in the stage of development of technology gives grounds for optimistic forecasts: mankind is facing a stalemate or in respect of the exhaustion of energy resources, either in terms of energy generated by environmental problems. There are real opportunities for the transition to alternative energy sources (inexhaustible and environmentally friendly). From these positions, modern methods of obtaining energy can be regarded as a kind of transition. The question is, what is the duration of the transitional period and what are the opportunities for its reduction.
References
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