Fish friendly turbine

Due to its design with fixed runner blades, the DIVE-Turbine has no gaps and is therefore considered a fish friendly turbine. It is operating with very low runner speed in full load and reduced runner speed in part load.  Thus, there is no risk of collision with rotating machine parts. 


  Characteristics Advantages for the fish


Maximum opening of runner blades in any operation point

 Low risk of collision


No gap between runner blades and shaft

No risk of pinch


Gap between runner blade and cylinder <2mm

No risk of pinch


Very long runner blades

Very low pressure gradient especially in combination with speed variable operation


Number of runner blades can be reduced to three

Low risk of collision


Low runner speed esp. in part load

Low collision speed

Runner speed control in migration periods

 „SoftStart“: Slow start with low speeds


Completely oil-free turbine

No risk of lubricant leakage




Speed variation and its effect on fish friendliness

Speed variation means that the runner speed of the turbine is reduced with sinking discharge (part load). The hydraulic effect of speed variation and the efficiency are comparable to Kaplan turbines with pitchable runner blades. The runner blades of the DIVE-Turbines are fixed to the runner shaft.


Regulation of  Kaplan turbine and DIVE-Turbine: the runner speed of the Kaplan turbine is constant. The runner speed of the DIVE-Turbine is reduced in part load.


Regulation of  Kaplan turbine and DIVE-Turbine: the runner speed of the Kaplan turbine is constant. The runner speed of the DIVE-Turbine is reduced in part load the runner blades remain opened. The collision risk is sinking with the reduced runner speed, while for the Kaplan turbine the collision risk is significantly rising in part load, as the blades are closing.


Mortality risk at full load and part load for Kaplan turbine and DIVE-Turbine: The mortality of the Kaplan turbine is rising significantly in part load, because the runner blades are closing. The mortality of the DIVE-Turbine is sinking in part load because the runner speed is reduced.  Due to the gap-free design of the DIVE-Turbine the mortality at full load is also assumed to be comparatively low.

The fish friendly behaviour of the DIVE-Turbine and specifically the positive effect of speed variation has been approved by practical research for fish length up to 25cm. More details on practical experiments  will be provided on request.





Proof of fish friendliness

DIVE Turbinen GmbH & Co. KG is offering site specific fish friendly power plant design and fish friendliness consulting.



Further advantages of the DIVE-Turbine for fish friendly power plant designs

Component DIVE-Turbine State of the art Kaplan Turbine
Guide vanes

Electronic drive

Leakage of lubricants impossible

Hydraulic drive and open hydraulic system

Possibility of significant leakage of lubricants


Contactless sealing, patented system free from wear and tear

Abrasion is impossible

Abradable seal

Abrasion particles in the water


Fully ecapsulated bearing

Leakage of bearing oil impossible

Bearing with classical sealing

Leakage of bearing oil possible

Bearing of generator

ONE central bearing for turbine and generator (no gearbox)

Minimum sound emmision

Separate bearing for turbine and generator

Ample need of lubricants

High sound emmision

Runner blades

Fixed runner blades

High overlap of blades also with three runner blades

High efficiencies

Pitchable runner blades with open oil hydraulic system

No overlap of blades with 3 pitchable blades

Low efficiencies due to missing overlap

Leakage of lubricants and hydraulic oil


Speed regulation

Very low runner speeds in part load

Fish friendly operation with low runner speeds in migration times (reduction of runner speed)

Pitchable runner blades

Critical, especially in part load when the blades are closing


Partnering with Natel Energy for FishSafe™ Turbine Designs:

To achieve unparalleled fish safety without the need for complex fine screens or bypass systems we partner with Natel Energy and their revolutionary FishSafe™ technology. At DIVE-Turbine, we've championed fish-friendly hydropower for over a decade. Our commitment to reducing fish mortality led us to pioneer fixed blade propeller turbine technology with speed variation, significantly outperforming traditional Kaplan turbines. In collaboration with Natel Energy, a leader in fish-safe turbine design, we're integrating their revolutionary FishSafe™ technology with our DIVE-Turbine concept. This partnership ensures our turbines achieve unparalleled fish safety without the need for complex fine screens or bypass systems.

The result? The DIVE-Natel turbine, combining the expertise of both companies to deliver high-performance, maintenance-free turbines that prioritize fish passage safety. Reach out to learn more about this groundbreaking solution.