Small hydro

Small Hydropower refers to the use of hydraulic energy through decentralized, small hydropower plants. In Europe, plant and equipment are up to 10 MVA power referred as small hydro power plants. This limit is arbitrary and in some countries it is higher, such as China 30 MW. Small hydropower plants operate on the same principle as large hydropower plants. They differ mainly by the performance class. There are also technical and historical distinguishing characteristics.

Applications

Small hydropower plants are in very different designs. Most plants are of small rivers and do not have a reservoir but above water basins of different size and design.

• Plants with capacities can contribute to decentralized energy storage.
• Dotierkraftwerke dine beneath large dams the waters with residual water
• Stand-alone systems not eat into the grid, but provide consumers in remote areas. Such systems are widely used in many developing countries.
• Classic small hydroelectric power stations use the potential energy in flowing water and are therefore run hydropower plants
• Drinking water plants use the excess pressure in water supplies which are supplied from sources in elevated positions.

Numerically, the majority of the hydropower plants belongs to the category of small hydropower; in terms of performance, the proportion varies depending on the region.

History

The history of small-scale hydropower in western Europe is closely linked to the history of industrialization. For driving of mills and machinery were already in the Middle Ages, waterwheels to tens of thousands of sites in use. Gradually grew in the 19th century, the competition from the steam engine that could be used independent of local conditions. At the same time, the technology of small hydropower plants to develop. Mill wheels were replaced, for example, early 20th century by Francis turbines, and increasingly served the facilities of electricity production instead of mechanical energy. The development was regionally very different. In Switzerland, for example, the eastern Plateau or the Canton of Glarus among the regions with a high density of traditional small-scale hydropower uses.

Types of power plants and their technique

The smallest form of a small hydropower plant is currently the water vortex power plant. In this type of flowing water is diverted by means of a short concrete ramp water and fed to a circular concrete tank with drain. The resulting water vortex drives a specially shaped vortex rotor generated by the resulting torque current.

As a type of generator beside the synchronous generators and induction generators are used. The latter can, however, do not provide reactive power available in the network, which is required for the regulation and stabilization in AC networks. For this reason, asynchronous only be used in smaller systems.

Environmental influences

Like any form of energy use also has the small hydropower impacts on the environment. Proponents of small hydropower argue, according to the latest standards and professionally built small hydro power plants, the water is not polluted, or in any case less than large power plants. Fishways and ecological support measures, how they are funded, for example, in the context of eco -labeling could, prevent damage, and often lead to an improvement. Opponents of small hydropower argue, small plants are not better than large ones. Barriers and low residual amounts of water were harming the ecosystems.