Hydropower Intake Design

The intake to a hydropower system is an extremely important but often overlooked aspect of good design, particularly for low-head schemes.

The intake must guide flow from the main watercourse into the hydropower channel with minimum losses whilst incorporating debris screens and sluice gates. Hydraulic losses are relatively larger in low-head sites since they make up a greater percentage of the available head, so the design becomes even more significant.     

Specific design guidance is hard to come by since no intake is the same and each offers their own challenges. The management of debris must also be considered as part of the design. Project designers seem to either replicate previous designs or simply revert to a standard design. 

VerdErg Renewable Energy has assessed the existing intake at the Eaton Socon hydro scheme in detail and gained significant insights in the design of efficient hydropower intakes by utilising the use of Computation Fluid Dynamics (CFD). Those lessons have already been applied to other projects in development. Understanding the behaviour of flow upstream of an intake is paramount to good design and this can only be fully understood through CFD or physical testing.  

The below intake is relatively standard with parallel wingwalls and a nicely rounded inlet into an existing channel. It is not an obviously poor design.  

Fig 1: Plan view of existing intake 

However, when assessing it using CFD, large vortices can be seen rendering the outside areas of the debris screen ineffective and thereby causing unnecessary head loss. This is also observed in situ. 

Fig 2: Existing intake suffering from poor hydraulic design 

Changing the inlet angle and avoiding the large radii on either side improves performance and reduces the head loss by 31 per cent. 

Fig 3: Proposed improvements to the intake, reducing head loss by 31% 

Taking the design a step further and just having large radii without wingwalls reduces the head loss by 61 per cent. 

Fig 4: Further design improvements of the intake, reducing head loss by 61% 

VerdErg Renewable Energy can provide guidance on the design of new hydropower intakes as well as provide solutions to improve the hydraulic performance of existing intakes. 

Contact us for more information:

Tel:     +44 (0) 203 696 4530

Email:  enquiries@verderg.com