Nearly the totality of the electric power come currently produced in systems that take advantage of the kinetic energy of a water mass in controlled fall (center them hydroelectric) or the thermal energy that is developed during a combustion process (centers them thermoelectrial).  Broadly speaking, this last case comprises also centers them to them nuclear, that they take advantage of the heat produced from one reaction nuclear.  In it centers them electrical workers fed to carbon fossil, the fuel comes polverizzao, stirred to air preriscaldata and iniettato in the combustion chamber of a water tube boiler, where she burns like a gas.  The room, or hearth, represents the greater structure of centers them;  the inner walls are covered from a series of tubes to serpentino, in which slide water, than they are developed for a total of various kilometers in order to extract the maximum possible heat from the fuel:  during the distance to the inside of the tubes, in fact, the water catches up the boiling point and it is transformed in overheated vapor and to high pressure.  A depurazione system filters combustion gases, so as to to extract the greater possible ash amount, before dispersing them in the atmosphere through one chimney.  In it centers them more modern the systems than depurazione they are plans to you placing particular cure to the extraction of sulphured slags, than they have been revealed extremely injurious for the atmosphere.  The vapor generated in the boiler comes sended to a turbine that transforms the thermal energy in mechanical energy, is pure with the low characteristic rendering of the thermal engines.  The vapor to low pressure and lowland temperature that exits from the turbine comes condensed and the obtained water comes newly pompata in the gallery of the boiler, closing the cycle.  The condensation of the vapor demands great cooling water amounts (approximately 230.000 m3 the hour for one centers them from 2000 mW), that it can be captured from a river or from a present lago in the vicinities of centers them, or must be recycle.  The recycling comes operated in the cooling towers, that they disperse in the atmosphere the residual heat and demand one relatively water amount reduced in order to satisfy that one lost for evaporation.  It centers fed them to diesel oil or to gas they work in analogous way.  In it centers them nuclear, instead, to generate heat is the reaction of fission of a combustible nuclear, that is of a radioactive material like the uranio.  The heat comes extracted from a coolant and therefore used in order vaporizzare one determined water amount for means of an appropriate said apparatus heat exchanger.  It is made successive of the process are analogous to those of centers them thermoelectrial.  They exist vary types of reactor nuclear, you base on structures and various cooling to you.  A series of bars of material with elevated ability to neutronica capture allows to control the reaction speed and can, in emergency case, to determine the complete extinction of the reactor, while a "biological screen" of concrete, often several meters, encircles the reactor in order protect the operating ones from the strongly radioactive emissions of the kernel.  You see Energy nuclear.  Recently it has had a much happened new type of centers them thermoelectrial with gas turbine, dictates to arranged cycle (CCGT, from English Combined Cycle Gas Upsets some).  In this type of it centers them the transformation of the thermal energy in the mechanical energy necessary to set in action a generating electrical worker happens in two times, with a rendering total that is approached 55%.  The combustible gas comes burnt in a coupled gas turbine a generating electrical worker and the exhaust gaseses come used in order to produce the vapor necessary to set in action one turbine to vapor coupled to according to generator.  In the electric power production, to the turbine, gas or vapor, the rotor of a generating electrical worker is coupled, usually an alternator constituted also from a fixed part, called stator.  The rotor is a cylinder of ferromagnetic, rotary material to the speed of 3000 turns to the minute, in which a winding covered from continuum flow is inserted.  For effect of the current that encircles it, the rotor behaves from electromagnet, producing therefore a rotary magnetic field.  The stator is constituted from a winding in which the magnetic field frequency of 50 generally induces tensions alternated variable with one Hertz (cycles to the second).  The produced mechanical energy from the turbine comes therefore transformed in electric power, with a next rendering to 100%.  Problems of production of the electric power the electric power is fundamental for the maintenance of the standard of living in the highly industrialized societies and is indispensable for the underdeveloped nations.  In the long term, however, the problem of the exhaustion of fossil and nuclear fuel is placed.  To it puts into effect them consumption rate, the esteem of duration of the supplyes go from 40-60 years for the natural gas and the oil, to 200 years for the carbon fossil.  A more pressing problem is that one of by-products of the combustion of carbon fossil, natural gas and derives you of the oil, that they are extremely injurious for the atmosphere.  I accumulate in the last few decades of carbon dioxide, the gas that more contributes to the effect greenhouse, comes considered the greater culprit of the increase of the temperature on the land surface (total heating).  Sources of electric power In order to reduce the fossil fuel consumption, are alone two possible alternatives:  the rinnovabili energy nuclear and energies.  After the incident of Cernobyl, that it has had a violent impact on the public opinion, in many countries has been suspended or reduced the operation of centers them nuclear, dangerous deductions for the public health and the atmosphere.  The energy amount that the Earth receives from the Sun is immense, however only one minimal part of it is usable.  Currently, the more promising sources than rinnovabile energy are the wind, the water and the biocombustibili, but the greater part of these so "is diluted" that for their exploitation numerous systems of large dimensions become necessary that would have a strong impact acclimatize them.  It centers them eoliche are constituted from groups of upsets of it to wind (or aeromotori) coupled to current generators.  In the encounter with the shovels of the turbine, the wind loses approximately 40% of the own kinetic energy, that it comes used in order to set in action the turbine;  the produced mechanical energy comes then transformed in electric power from the generator.  The solar light comes directly transformed in current continuous electrical worker (with a rendering of approximately 15%) from dispositi to you fotovoltaici constituted from material semiconductor.  The continuum flow must then be transformed in alternating current for being able to be immessa in the distribution network.  You see Feeding and distribution of the electric power.  In the hydroelectric systems, the kinetic energy of the water that falls through an unevenness comes transformed in mechanical energy from one hydraulic turbine coupled a generating electrical worker.  In some it centers them thermoelectrial, the heat comes produced from the combustion of refusals or methane obtained from the decomposition of refusals.  In others "biocombustibili" are used, that is material of coming from refuse from agricultural procedures, or firewood obtained from the cut of plantations purposely cultivated.  A serious engagement in the search of sources of rinnovabile energy could carry in the future to systems of small dimensions bases to you on diversified technologies, that they would replace large the central-cathedral today.  One centers them electrical worker is an industrial system action to the electric power production.  The modern society is by now based in unavoidable way on the use of the electric power, therefore the production of such energy and consequently centers them them electrical workers has one fundamental technological and strategic importance.  It centers them electrical workers odierne produce energy exclusively in alternating current nearly (exist exceptions in Russia, where for problems of losses on elettrodotti extremely long they have been created centers them electrical workers in continuum flow), taking advantage itself of blots of it called electrical workers alternators.