Swiss hydropower plant automated with Siemens technology
In the small town of Lützelflüh in the Emmental district of Switzerland, “green” electricity is generated in the Gohlhaus small hydropower plant. The system, which features one of the largest permanent magnet generators in Switzerland, is automated with Siemens technology and is set to supply around 600 households with sustainably produced electricity if everything goes to plan. In addition, the small hydropower plant also makes a valuable contribution to the local ecosystem, as the fish ladder on the power plant building now enables fish to migrate upstream and downstream.
In the tranquil and picturesque district of Emmental in Switzerland – which is also the original home of the medium-hard cheese Emmentaler – a natural barrier in the river Emme offers ideal conditions for using a hydropower plant to generate electricity. So, last year the Gohlhaus small hydropower plant was connected to the grid downriver of the Gohlhaus bridge in Lützelflüh, where it supplies a planned annual output of 2,200 megawatt hours (MWh), which is enough to provide nearly 600 households with electricity generated from a renewable energy source. One of the largest permanent magnet generators in Switzerland is used to ensure that it runs efficiently, and this in turn is controlled via Siemens automation components.
Reliable control, easy to program
The most distinctive feature of the small hydropower plant is its two large weir flaps, which are used together with the bottom outlet and the flushing gate to dam the river Emme in the Emmental district of Switzerland. The almost 4-meter difference in water level achieved in this way is used by the small hydropower unit to generate electricity. In the process, the inlet structure directs up to 16 cubic meters of water per second to the turbine. Bars arranged horizontally with a spacing of 20 millimeters form a trash rake, which prevents flotsam like branches and leaves from getting into the turbine. Control for the overall system is provided via a Siemens Simatic S7-1511 system with ET 200MP distributed I/O modules. “We use the same components to control the four hydraulic power units, all flaps and the ventilation of these components,” says Patric Bertschy. He is a technician at Kobel Elektrotechnik AG, a company that has been developing open and closed-loop control systems for small power stations for 40 years. The components are engineered and programmed in the Totally Integrated Automation (TIA) portal. Data can be remotely accessed via a Smart Server. “We can read all of the values from anywhere in real time and, in some cases, also confirm them. However, we prefer to implement changes on site. This allows us to have a proper look at the situation and actually listen to what the turbine and generator sound like,” explains Bertschy.
Sustainable, long-term impact
In addition to the sustainable production of electricity, the power plant offers another important advantage for the region. Thanks to the fish ladder on the power plant building, fish can now also migrate upstream along the river Emme. Peter Kast, Managing Director of KW-Gohlhaus AG, is delighted: “The power plant combines two small barriers into one. The larger of the two was an impassable obstacle for fish. Now, the fish are able to migrate upstream and downstream again, allowing them to spawn and feed freely.”