What is a central power plant

power plant

Lexicon> letter K> power plant

Definition: a system for generating electrical energy

More general term: energy producer

More specific terms: large power plant, decentralized power plant, thermal power plant, thermal power plant, nuclear power plant, coal power plant, gas power plant, oil power plant, wind power plant, tidal power plant, solar power plant, geothermal power plant

English: power station

Categories: electrical energy, prime movers and power plants

Author: Dr. Rüdiger Paschotta

How to quote; suggest additional literature

Original creation: 07.03.2010; last change: 20.11.2020

URL: https://www.energie-lexikon.info/kraftwerk.html

Power plants are industrial plants with the main purpose of generating electrical energy. However, some power plants have additional functions such as providing heat (→Thermal power station), regulating the amount of water in rivers, or producing plutonium for nuclear weapons.

The term power plant may be surprising at first, since electrical and not mechanical energy is supplied. However, mechanical energy can easily be obtained from electrical energy using electric motors, and this is in fact one of the most important uses of power from power plants.

Types of power plants

Power plant units

Many power plants consist of several Power plant blocks lower power, which can be operated independently of each other. In a coal-fired power station, for example, a power plant block has its own furnace, a steam generator, a turbine set and a generator, while other parts of the infrastructure (e.g. a coal store) can be shared with other blocks. Such a power plant unit typically has an output of a few hundred megawatts, and a combination of several units can produce outputs of several gigawatts. Splitting up into several power plant blocks has various advantages:

  • The performance can be better adapted to the respective demand by only operating some of the blocks, if possible, but with full load if possible. The partial load operation of a single larger block would be comparatively less efficient.
  • The maintenance work can be carried out for the various units at different times, so that the entire power plant never fails because of it.
  • Unplanned outages usually only affect one block, so the security of supply is higher than if only a very large block were operated.

However, power plant blocks should not be too small either, since the highest degree of efficiency can only be achieved with very large turbine systems (with hundreds of megawatts) and the specific costs are also higher for smaller blocks.

Central and decentralized power plants

Power plants are also differentiated according to their size:

The article on decentralized power generation discusses the advantages and disadvantages of decentralized power plants compared to large-scale power plants.
  • Headquarters Large power plants are systems with outputs of hundreds of megawatts or even more than 1 GW. They supply entire cities or regions with electrical energy. The use of waste heat through combined heat and power generation is made very difficult by the fact that hardly enough consumers for heat can be found in good spatial proximity.
  • Small power plants that are decentralized and close to the consumer do not have this problem. As combined heat and power plants, for example, they supply individual apartment blocks or industrial plants, whereby the entire waste heat can often be used. However, the electrical efficiency is typically significantly lower than that of large power plants. As explained in the article on combined heat and power, this is particularly important for evaluating energy efficiency. Other disadvantages are the higher specific investment costs and often the dependence on higher quality and more expensive fuels such as natural gas or diesel fuel.

Besides the technical and energetic aspects there is for the question central vs. decentralized also others who affect social and political issues. In particular, decentralized solutions are often particularly popular due to the fact that they are closer to the citizens and can therefore, under certain circumstances, facilitate the implementation of issues such as climate protection. One speaks of “power plants in the hands of the citizen” when they are operated by individual citizens, by energy cooperatives or by municipal utilities.

There's the concept of virtual power plant, in which a large number of small, decentralized power plants are combined to form a network. On the demand side, it can behave in a similar way to a large power plant.

Use according to load types

Power plant disks

There are contracts that guarantee an electricity consumer a certain proportion of the generation of a power plant in a certain (mostly long) period of time. One often speaks of a “power plant disk”. Such agreements relate purely to the power generation of the power plant and do not imply any financial participation in the power plant itself. There is therefore no participation in the financial risks of the power plant operation, apart from the risk of insolvency.

Connection to electricity networks

As a rule, a power plant is not connected to a specific consumer, but to a public power grid. Large power plants are always connected to the transmission network via a powerful power plant connection line, because only this can absorb very high outputs. Smaller power plants, such as open-space photovoltaic systems, are often connected to the medium-voltage network.

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See also: thermal power station, heat engine, thermal power station, combined heat and power, electrical energy, coal-fired power station, gas-fired power station, oil power station, combined cycle power station, nuclear power station, hydroelectric power station, large-scale power station, decentralized energy generation, solar power station, wind turbine, virtual power station, base load, Medium load, peak load
and other items in the electrical power, prime movers, and power plant categories