Storage power plant (water)
As storage power plant (full name water storage plant or storage hydroelectric power plant ) in connection with the is hydropower a storage power plant called, the electrical energy in the form of potential energy (potential energy) of surface water stores .
For this purpose, in times of energy / water surplus, the water of a river is dammed into a reservoir , from which it can flow off in times of increased energy demand and generate electricity in a hydropower plant . In the case of pumped storage power plants , the water can also be pumped into the reservoir using energy.
Water storage power plants serve - like all storage power plants - above all to cover peak performance and, within the framework of network regulation, they contribute to maintaining control power .
Storage power plants differ from run-of-river power plants in that the former only have a very small usable storage volume. In run-of-river power plants, any dam structures that may be present primarily have the task of increasing the height of fall for the turbines. Since there are also run-of-river power plants that can vary the fill level in a certain range ( threshold operation ), there is no clear boundary between run-of-river power plants and storage hydropower plants.
motivation
There are several reasons for building storage power plants. Electric power grids cannot store electrical energy. Consumption and energy generation in power plants should be as balanced as possible. Deviations from the equilibrium state lead to network disturbances and, in extreme cases, to a network breakdown . In terms of technology and principle, conventional power plants cannot react quickly enough to fluctuations in consumption or provide power quickly enough in the event of brief, high consumption peaks. Storage power plants take on this task. They serve as water and energy storage. Technically, they are designed so that they can deliver electrical power as required in a short time. Depending on the system, the power range is from a few megawatts to over 1000 MW and is usually sufficient for several hours in full load operation.
The function as a water reservoir can serve both the water management regulation and special tasks such as the storage in the drinking water supply . The Sylvenstein reservoir in Bavaria was originally built for flood protection . Here, as in some other cases, the use of hydropower is only of secondary importance. Sylvenstein II generates 3.8 MW. Goldisthal , the largest storage power plant in Germany, 1,060 MW.
In addition, this type of energy generation is considered renewable energy and therefore climate-friendly. Seawater pump storage power plants are a special technique.
Construction of a storage power plant with water
Dam
The water is collected in a basin called a "reservoir". This lake is either of natural origin or is created by damming with a dam or dam . The reservoir is fed by a natural inflow, in addition tunnels are often built to the catchment areas of other rivers in order to increase the amount of water flowing in. If the water is pumped into a higher basin (also called upper basin or reservoir), it is called a pumped storage power plant .
Headwater supply
The water is stored and, if necessary, fed through a pressure tunnel and / or pressure pipes to the lower-lying machine house. On the last section of the pressure line, often also in the transition area between the tunnel and the pipeline, there is often a surge tank .
Machine house
The pipes open into the machine house , where the water pressure is up to 200 bar . Here the water hits the turbine , sets it in rotation and transfers its potential energy to the turbine. This drives the generator that produces the electricity . The water then enters the lower basin. The lower basin is often itself a reservoir, which in turn is used as an upper basin for other hydropower plants. In storage power plants, either Francis turbines or Pelton turbines are used , depending on the head and the amount of water available .
features
Depending on the filling / emptying rhythm, storage power plants are divided into daily, weekly, monthly and annual storage. In the Alps in particular , storage power plants often function as annual storage. When there is a relatively low inflow of melt water from glaciers , the water is stored in the summer half of the year in order to produce electricity mainly in the snowy but arid winter half of the year. The water storage is either dammed naturally or with a dam or dam.
The storage power plant's output is available within minutes if required and can be flexibly regulated over a wide range. This is an advantage compared to medium and base load power plants , the output of which can only be easily adjusted in the range of several hours. This property makes it possible to cover the electricity demand at peak times . In addition, a storage power plant can temporarily bridge the failure of other power generators.
Storage power plants are black start capable and can therefore be used to start up other power plants in the event of total power failures.
literature
- Adolf J. Schwab: Electrical energy systems: generation, transport, transmission and distribution of electrical energy . 2nd Edition. Springer, 2009, ISBN 978-3-540-92226-1 .
- Horst Völz : Storage as the basis for everything. Shaker Verlag, Düren 2019, ISBN 978-3-8440-6964-8 .
Web links
- Electricity online - storage power plant
- Dresdner Latest News: Alternative Energy from the Power of Water
Individual evidence
- ↑ Bayerische Landeskraftwerke GmbH: Sylvenstein I and II ( Memento of the original from January 31, 2017 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
