About Energyminer GmbH
Energyminer GmbH is an innovative technology company based in Gröbenzell near Munich that specializes in the development and operation of floating tidal current power plants. The company’s goal is to enable a renewable, baseload-capable, decentralized, and environmentally compatible energy supply by harnessing the kinetic energy of freely flowing waters.
With the Energyfish, Energyminer has developed a novel hydrokinetic power plant concept that requires no dams or interventions in the river system while still generating electricity continuously. The technology combines engineering precision with ecological sustainability and thus contributes to transforming the energy supply toward a CO₂-free and resilient infrastructure.
A Floating Tidal Current Power Plant
The Energyfish is a floating tidal current power plant that is anchored in the riverbed and uses the energy of the water current for sustainable electricity generation. Thanks to its compact design, the system is located almost entirely underwater and is therefore barely visible, which is particularly advantageous in sensitive environments.
Unlike weather-dependent energy sources such as wind or photovoltaic systems, the Energyfish is baseload-capable and ensures continuous energy production regardless of weather conditions and season. The design is fully flood-resistant: when water levels rise, the system submerges automatically and continues to operate continuously.
In addition, the system is designed for low maintenance requirements and high availability, making it particularly suitable for long-term use in flowing waters. Aquatic life is neither injured nor disturbed in its natural behavior.
Photo: © Energyminer GmbH
Energy Generation in a Swarm
The Energyfish is designed for operation in so-called swarm power plants. In this setup, several individual systems operate together within a section of a river and feed the generated energy into the local low-voltage grid via shore stations. Instead of one large centralized power plant, this creates a modular system that can be flexibly adapted to the location, flow conditions, and power requirements. By distributing the system across several compact units, a considerable overall output can be achieved.
Photo: © Energyminer GmbH
System Concept and Technical Implementation
The Energyfish follows a flow-based system concept that deliberately avoids interventions in the body of water. Instead, the natural dynamics of the river are used, which requires precise coordination of hydraulics, mechanics, and control technology. In particular, the interactions between flow behavior, buoyancy forces, and the long-term behavior of the materials used play a crucial role in stable and efficient operation.
Inside the system, a robustly designed, highly efficient turbine system operates, driven directly by the flow velocity of the water. The electrical energy generated is fed into the local low-voltage grid via the connected shore stations. The system is positioned in the river by anchoring it to the riverbed with an anchor cable. Conventional load shackles without integrated force measurement are currently used for this purpose. The aim here was to learn more about the forces acting on the anchoring of the Energyfish on the riverbed.
Graphic: © Energyminer GmbH
Measurement Technology Used: SHK-B Series Load Shackle
For the project, a bow-type load shackle from the SHK-B series, type SHK-B-Z6197-2t, was selected. It is designed for precise load measurements under demanding conditions. The series covers measuring ranges from 1 to 1,000 tonnes, optionally up to 2,000 tonnes, and thanks to IP67 protection as well as ATEX/IECEx approval from 3.25 tonnes upward, it is also suitable for harsh and potentially explosive environments. In this case, a two-tonne IP68 shackle with an internal 4–20 mA measuring amplifier was selected.
The load shackle offers high measuring accuracy with an output signal of 1.8 to 3.6 mV, non-linearity of <±1%, and repeatability of <±0.1%. Signal amplification or telemetry are optionally available. All load-bearing components are fully certified.
It can be used in a temperature range from –20 to +70 °C, with compensation from –10 to +50 °C. Connection is made via a 10 m PUR connection cable. Overall, the SHK-B series represents a robust and reliable solution for industrial load measurements.
Results and Added Value of the Load Measurement
The new sensor-equipped SHK-B load shackle from Althen provides additional measurement and monitoring functions on the Energyfish. It is positioned between the anchoring and the retaining cable and enables continuous recording of the actual loads occurring during operation. The measurement data is reliably transmitted via the wired 4–20 mA output signal.
By integrating the sensor-equipped load shackle, the existing monitoring concept of the system is further expanded. Critical load conditions, such as overload, a loosening anchor, or an imminent cable break, can be detected even earlier and specifically checked as part of planned maintenance measures.
In addition, the measurement data obtained provides a sound basis for interpreting occurring vibrations, which in this case are mainly caused by wave motion. Through direct force measurement, these effects can now be classified much more clearly and distinguished from the structural behavior of the system.
The new load shackle is currently in use on a single system and serves as a reference for further investigations. Further development and possible scaling of the solution to several systems within a swarm power plant is already being planned.
Quelle: https://energyminer.eu
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