Wasserkraftwerk Hohenstein

Gazing at the Wasserkraftwerk Hohenstein, one might mistake it for a romantic castle. Its Ruhr sandstone facade, reminiscent of the nearby Ruhr Viaduct, exudes a timeless charm. But don’t let the exterior fool you. This old fortress on Wetterstraße houses a young heart. The Wasserkraftwerk Hohenstein, built in the early 1920s by the Schaufelfabrik Bredt & Co., seamlessly blends history with modernity. Inaugurated in 1924, the Wasserkraftwerk Hohenstein has been tirelessly generating power from the Ruhr’s flow. Inside, a starkly modern world unfolds. The machine hall, bathed in white, showcases the angular steel-reinforced concrete beams of the roof structure. These beams contrast sharply with the black-lacquered machinery. Even the sepia-brown wall tiles and beige-black patterned floor tiles play their part in the power plant’s coordinated color scheme. Originally, three Francis turbines powered the Wasserkraftwerk Hohenstein. These generated a combined 1.75 megawatts, equivalent to 2800 horsepower. In 1996, a modern generator replaced the original turbines after they suffered damage. Now, the powerhouse runs around the clock. The Wasserkraftwerk Hohenstein can handle a maximum water flow of 75 cubic meters per second. This is equivalent to filling approximately 400 bathtubs. With a drop height of about four meters, the plant generates up to ten million kilowatt-hours annually. This output meets the annual electricity needs of about 3000 households. The process starts with three gates controlling the water inflow. Each gate leads to a turbine, protected by screens to catch debris. The water then flows into the turbine, where its energy transforms into rotational motion. Fixed guide vanes channel the water onto a large shaft holding the rotating impeller. This impeller, resembling a ship’s propeller, drives the generator, feeding electricity into the public grid via an underground cable. Usually, the Wasserkraftwerk Hohenstein operates remotely. Employees rarely visit, as the control center in Herdecke manages everything. This center oversees not only the Witten plant but also twelve other plants along the Ruhr. In 2018, Innogy, the “green” subsidiary of RWE, started building a new fish ladder. This 127-meter-long structure, comprising 33 consecutive basins, makes it easier for fish to bypass the dam. This new “fish ascent facility,” built near the turbine outlets where the main current flows, complements the older fish ladder, which remains preserved. More recently, in 2022, the weir underwent extensive restoration. This weir creates a 3.4-meter height difference between the water levels upstream and downstream of the turbines, enhancing the flow’s energy. From a romantic exterior to a modern interior, the Wasserkraftwerk Hohenstein offers a unique blend of history and innovation, silently powering thousands of homes while respecting the river’s ecosystem.