Small hydropower
Small hydropower refers to the use of hydraulic energy by decentralized, small hydropower plants . In Germany the upper limit is given at approx. 1 MW , in Europe plants with an output of up to 10 MW are referred to as small hydropower plants. This limit is arbitrary and in some countries it is higher, e.g. B. China 30 MW. Small hydropower plants work on the same principle as large hydropower plants. They mainly differ in their performance class. But there are also technical and historical distinguishing features.
Applications
Small hydropower plants come in very different versions. Most of the systems are located on small rivers and do not have a reservoir, but water basins of various sizes and types.
- Systems with storage capacities can decentralized energy storage contribute
- Doping power plants feed the water with residual water underneath large dams
- Diversion power plant z. B. for the Grazer Mühlgang at the Graz-Weinzöttl power plant
- Stand- alone systems do not feed into the grid, but supply consumers in remote areas. Such systems are widespread in many developing countries
- Classic small hydropower plants use the energy of rivers very continuously and are therefore run-of-river power plants
- Drinking water power plants use the excess pressure in water supplies that are fed from sources in elevated locations
In terms of numbers, the majority of hydropower plants belong to the category of small hydropower; In terms of performance, the share fluctuates depending on the region.
Other media
- Pipeline power plants use the height of fall of the liquid transport medium after comparatively steep downhill passages, but only recycle part of the pumping effort on the uphill section before.
- Conveyor belts for mined minerals that run significantly downhill can expediently generate electrical energy using motor generators.
history
The history of small hydropower in Western Europe is closely linked to the history of industrialization . To drive mills and other work machines , water wheels were already in use at tens of thousands of locations in the Middle Ages . Gradually grew in the 19th century competition from steam engines and traction engines that could be used independent of local conditions, but also consumed expensive fuel. At the same time, the technology of small hydropower plants developed further: Many water wheels were replaced by Francis turbines at the beginning of the 20th century , and the systems were increasingly used to generate electricity (also called "power mills" based on water mills). Depending on local hydraulic engineering requirements and the resulting willingness to invest and economic orientation, the development varied greatly from region to region. Mountainous regions with reliably high levels of precipitation even in summer offer classic prerequisites for a high density of traditional small hydropower use. In Switzerland, for example, this applies to the eastern central plateau or the canton of Glarus . In Germany, mining in the Harz was associated with extensive use of small hydropower ( Harzer Wasserregal ).
Power plant types and their technology
The smallest form of a small hydropower plant is currently the water vortex power plant . With this type, water is branched off from a flowing body of water with the help of a short concrete ramp and fed to a circular concrete basin with a drain. The resulting water vortex drives a specially shaped vortex rotor, which generates electricity through the resulting torque.
Turbines convert the energy of the water from a height of 2 m. Tube and Kaplan turbines are suitable for this. Francis and especially the more complex Pelton turbine are used for greater heads.
As a type of generator in addition to synchronous generators and asynchronous generators used. The latter, however, cannot provide any reactive power in the network, which is required for regulation and stabilization in AC networks. For this reason, asynchronous generators are only used in smaller systems.
Environmental influences
Like any form of energy use, small hydropower also has an impact on the environment. Proponents of small hydropower argue that according to the latest standards and properly built small hydropower plants do not pollute the waters, or at least less pollute than large power plants. Fish ladders and ecological accompanying measures, such as B. financed in the context of green electricity labeling, could prevent damage and often even lead to an improvement. Opponents of small hydropower argue that small systems are no better than large ones. Buildings and insufficient residual water damage the ecosystem. In exchange for a very small amount of electricity, great damage in terms of biodiversity is accepted. The oxygen content of the water, its temperature and, to a certain extent, its self-cleaning ability can also be negatively influenced by hydropower plants. After all, there is less fresh water that a natural river can use to clean itself.
Hundreds of small hydropower plants in Switzerland are not subject to the Water Protection Act because of marital rights .
literature
- Jürgen Giesecke, Emil Mosonyi , Stephan Heimerl: Hydropower plants - planning, construction and operation . 5th edition, Springer, Berlin a. a. 2003, ISBN 978-3-540-88988-5 .
- Bernd Uhrmeister, Nicola Reiff, Reinhard Falter: Save our rivers - critical thoughts on hydropower . Pollner, Oberschleißheim 1998, ISBN 3-925660-59-3 .
- Michael Hütte: Ecology and Hydraulic Engineering: Ecological Basics of Water Construction and Hydropower Use . Parey / Vieweg, Berlin / Vienna / Wiesbaden 2000, ISBN 3-528-02583-2 (Vieweg) / ISBN 3-8263-3285-7 (Parey).
Web links
- Research project on the history of small hydropower - Technical University of Darmstadt
- Swiss Small Hydro - Swiss Association of Small Hydropower (formerly the Association of Swiss Small Power Plant Owners ISKB)
- Federal Association of German Hydropower Plants
- Small hydropower association Austria
- Small hydropower program from EnergieSchweiz
- Small hydropower plants: the renaissance of watermills? , Report from 3sat-hitec in March 2011
Europe
Individual evidence
- ↑ Deutschlandfunk Nova of September 21, 2018: First pipeline power plant in the Alps , accessed on February 2, 2020
- ↑ Innovation report from November 11, 2008: "Power plant made of ore": Conveyor belt generates electricity , accessed on February 2, 2020
- ↑ The dark side of hydropower. July 22, 2019, accessed November 30, 2019 .
- ^ Daniel Bütler: Small hydropower plants need new concessions. In: observer.ch . June 6, 2019, accessed June 24, 2019 .