Energy engineering is a specializedspreading engineer science. Both machine-builder (turbines, boiler, reactors), electrical engineer (generators, transformers, regulation) and civil engineers (embankment construction, turbine house) concern themselves among other things with the efficiency of energy production, energy conversion, energy transfer and energy use.

Energy production

A majority of our daily available energy is produced as electric current in power stations. Different kinds are converted from primary energy carriers (coal, gas, sun, uranium, wind) into Nutzenergie (river, warmth). The need of energy in a public electrical energy net is strongly coined/shaped of seasonal fluctuations. In the summer less river is needed for light and warmth than in the winter. Also during a daily large fluctuations arise. So a peak of requirements of electric current of a public net is above all in the morning between 6-8 o'clock to notice between 11-13 o'clock and between 19-22 o'clock. Electricity cannot be stored until today to considerable extent. Hence it follows that production and consumption of the electricity must always be in the equilibrium. This leads to a regulation of the net and the power stations. Fluctuations with the need of regional electricity mains become balanced, by interconnecting several regional electricity mains and so a homogeneous process of the need curve reached.

Kinds of power station

Partitioning after the distribution of load

• Baseload power stations:

These stress high capital outlays, have for it however small operating cost. As consequence they are thus economical only if they exhibit very long yearly periods of operation. Starting baseload power stations stresses in extreme cases up to several days. They produce the majority of the river used in Europe.

As baseload power stations above all river-run power plants, nuclear power stations and brown coal power stations are used.

• Mean load power stations:

These are in the capital outlays and/or operating cost between the reason and peak load power stations and are appropriate to adjust larger fluctuations in the course of the day of the power supply.

As mean load power stations above all hard coal power stations are used.

• Peak load power stations:

They have to close the task of supply deficits of the energy supply. Small capital outlays and high operating cost make the river from peak load power stations very expensive. This is also the reason for only small periods of operation of peak load power stations. They can be started however very fast. A typical example of peak load power stations are pump-fed power stations. Germany must very often buy to go with river in point times from its neighboring countries to high prices. 2003 were established the pump-fed power station largest in Germany (pumped storage power station Goldisthal) in the forest.

The more generator to be established, which unstably river produce (wind force, Photovoltaik) becomes the larger the meaning of peak load power stations.

Partitioning after the primary energy carrier

• Fossil energy:

Coal-fired power stations

In a burner area coal is burned. The produced heat energy is used to evaporate in a water-tube boiler water. The water vapour is overheated, it forms for steam with a very high temperature and under very high pressure. Subsequently, it is eased in a steam turbine, possibly with resuperheating, the temperature and the pressure falls. The water is however still present as steam. Behind the turbine the water vapour in a condenser is liquefied, so that at the conclusion again water is present. This water is back-fed over the feed pump into the boiler. This particularly cyclic process is called Clausius Rankine process. The propelled turbine propels a generator, which produces river over a wave.

Gas-turbine electric power stations

With gas-fired power stations in a gas turbine similarly an airplane engine a compressed, thus mixture from air and gas, which is at high pressure, is ignited. The expansion of this mixture propels the wave, to which a generator is attached in the gas turbine. Air is sucked in and compressed at the entrance of the gas turbine under ambient pressure and temperature. In the combustion chamber gas is injected and ignited. This is exotherms a reaction, it energy is thus set free. In the actual turbine the burned mixture is then expanded, i.e. the pressure and the temperature to sink and will transfer the kinetic energy of the mixture to the rotor blades of the turbine. These turn and continue to transfer the torque to the wave, which propels finally the generator.

GuD power stations

GuD power stations are combined gas and steam power plants. With a gas turbine air at the withdrawal has still another high temperature. This can be used around water, similarly as with steam power plants to evaporate. GuD power stations achieve a higher efficiency than individual steam or gas-fired power stations.

Long-distance heating power stations

Long-distance heating power stations can be realized only in close proximity to centers of dense development, since the produced warmth in the direct environment must be removed. Long-distance heating power stations are frequently combined with steam power plants, can be operated however also individually. With the combined heat and power stations the remaining energy of the water at the turbine withdrawal is used. Steam is cooled down not up to ambient temperature but fed with a higher temperature level by large pipings into a long-distance heating net. With the consumer steam delivers then its warmth and returns as water with smaller temperature again to the power station.

• Power stations with regenerativ energy sources

Hydro-electric power plants

Hydro-electric power plants occur in very different form and for very different targeted applications. Baseload power stations are e.g. very large pilot hydro-electric power plants like or the three-ravine dam. They are operated with large Francis water turbines. These are water turbines for a middle head and a middle flow. They reach achievements of up to 800 MW per turbine and power station achievement of up to 12,6 GW. Also run hydro-electric power plants (river-run power plants) like the run hydro-electric power plant are used as baseload power stations. A large flow and low heads which are characteristic mittlels a Kaplan turbine or a Francis water turbine for power generation to be used. Storage power stations like the power station Walchensee serve particularly for the cover of requirements of electric current in point times.

• Wind-powered devices
• Fotovoltaik
• Geothermie

Regulation

River produced as the rotor of a generator into a rotating motion is shifted. In large power stations these generators are excluding synchronous machines. Such a synchronous machine produces a rotary field by means of its rotor, into whose coil a direct current flows. This field induces out of phase sinus-wave voltages over in each case in the three coil windings of the stator three 120"°.

Now if requirements of electric current of electricity mains are increased, then the generator must furnish more achievement. Thus for example steam or water turbine must transfer a larger achievement to the generator. She does not do this the generator due to the larger resistance will more slowly run. Thus thus also the frequency changes - it becomes smaller up to the load decrease. The frequency is thus a characteristic characteristic which requirements of electric current of a net describes. And power stations are actually regulated after the frequency of electricity mains. It is too low must steam or gas turbines more achievement bring. It is too highly the achievement is reduced.

For this complex control engineering is necessary. In large electricity mains many energy producers are connected with one another. Among themselves co-ordinated now the necessary quantity of electricity must be made available.

The supply actually depends on river however on still further influences. The German current market is liberalisiert and river on the current stock exchange in Leipzig and Frankfurt/Main like a commodity is acted since the entry into force of the power industry law in April 1998. Large power supply firms (EON, RWE, public utilities etc.), in addition, private customers and industrial enterprises buy with power station operators river. Depending on how much river a power supplier it is thus sold to also produce.

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