top of page


In May 2013, VerdErg Renewable Energy completed a fish testing programme in collaboration with Vis Advies BV at their facility in Nieuwegein, The Netherlands. The aim was to assess the passage of riverine fish through a full scale instrumented VETT model and determine their survivability with special focus given to juvenile fish due to their vulnerability to extreme hydrodynamic conditions in hydropower systems.

As the turbine in the secondary circuit will always be screened, the testing programme focussed on the hydrodynamic conditions (including a negative pressure transient) that fish will experience when passing through the VETT’s primary circuit and venturi.

In total, 827 fish were tested comprising of European eel, Atlantic salmon, Rainbow trout and Round Goby.


Using the “forced exposure method” developed by Vis et al., 2011, these fish were tested at 3 different head drops: 1.0 m, 1.5 m and 2.0 m with a maximum flow rate of 450 l/s.

Independent Third Party Verification was conducted by Dr Billy Sinclair at the University of Cumbria which was funded by the Technology Strategy Board Innovation Voucher Scheme. No immediate or latent or internal or external injuries from passage were observed for all test scenarios rating the VETT a maximum score of 1 with classification “Outstanding”.


VerdErg with Vis Advies Project team and Dr Billy Sinclair

As the VETT is scalable, these findings can be extrapolated to tidal and river sites with the same hydrodynamic profiles.

These research outcomes inform key concerns with fish migration especially of salmonids and eels and have relevance to the efforts to restore their populations. These finding demonstrate that hydropower can be environmentally sustainable.


VerdErg hopes to follow up this milestone achievement with a long term fish testing programme as may be required to address specific project issues in collaboration with the University of Cumbria Energus Campus.

The Vis Advies report can be downloaded below and the Third Party Verification report can be accessed here.

Download PDF – Test on fish survivability of the”Venturi Enhanced Turbine Technology”


We are here to assist. Contact us by phone, email or via our social media channels.

bottom of page