At STW, active environmental protection is our daily business. Since the founding of the company in 1919, and not least, because our headquarters are located in a health resort, environmental protection, as well as sustainable thinking and action have been important, founding principles of our company tradition; from raw materials to machinery, from development, production and processing to final fibre products and dispatch.
This is what we mean by active environmental protection:
THE TOPIC OF CORPORATE ENVIRONMENTAL PROTECTION IS A MATTER OF COURSE FOR US. FOR THIS REASON, WE USE THE POWER OF NATURE AND HAVE BEEN DOING SO FOR DECADES.
Through the use of residual materials such as textile waste materials, we produce our high-quality fibre products in a particularly environmentally friendly manner. In addition, our fibres have been used to replace environmentally harmful substances such as asbestos in different applications.
Our sustainable thinking is also appreciated by our customers. Thanks to their exceptional quality, STW fibres are preferred for the development of new environmentally friendly products!
Hydroelectric power plants in Gengenbach and Offenburg
In Gengenbach and Offenburg, STW uses hydroelectric power plants to generate electricity. When the water level is high enough, 20,000 litres per second flow through the turbines. This roughly corresponds to the amount of water needed to fill 130 bathtubs.
Kaplan tubular turbines are used as the turbines in both plants. They are like a large ship's propeller with adjustable blades. The more water the Kinzig carries, the wider the gap in the Kaplan turbine opens and the higher its output. At low flow rates, the turbine closes so that the upstream water level is kept constant. Since the generator is coupled directly to the turbine, the Gengenbach and Offenburg power plants have a very high total efficiency of more than 90 %.
Most of the technology is hidden in an underwater module. This is what makes the facilities in Gengenbach and Offenburg so special. Only the switchgear, a few ancillary units and the transformer, which converts the electricity to 20,000 V and feeds it into the medium-voltage grid, are located in the turbine house.
The special construction allows the position of the systems to be changed according to the water level. The power house can be raised in the event of flooding, thereby increasing output. Fish that do not use the fish ladder or the fish steps can also swim under the system. At the same time, the natural bedload transport (gravel and stones), which contributes significantly to improving the water ecology, is not blocked by the hydroelectric power plant. This keeps adverse influences on the Kinzig to a minimum.
The particularly environmentally friendly construction was also evidenced by the funding of the systems as part of an EU Life project and the German Federal Foundation for the Environment.
Diversion power plants in Grubersgrund, Mühle, Aue and Vortall
The hydroelectric power plants in the municipality of Schenkenzell are all diversion power plants that generate their output mainly from the difference in altitude when the water volume is low. The Vortal system only uses a maximum of 1,200 l/s, but generates a maximum output of around 250 kW thanks to its drop height of 27 m.
All plants have a weir that controls the discharge of the water flow, an unpressurised headwater channel that leads the water to the rake cleaner, a rake cleaner that keeps leaves, branches and fish away from the turbine, and a pressure line that makes the difference in height usable for the turbine.
All STW systems are equipped with the latest fish protection systems and produce CO2-free green electricity around the clock. This means the plants make an active contribution to the regional energy transition and, in some cases, have been doing so for over 100 years.
The annual production of the plants is as follows: