FAQs

I need to bring my scheme up to standard. How can I meet current requirements yet increase my generating capacity?
By installing a screw turbine, not only will you meet current requirements on water usage and fish protection, you can also pay off and even secure a return on the installation of a fish pass.

Are screw turbines suited to instream flows?
Completely. Screw turbines are ideal for instream flows. Heads, flow rates and their constancy ensure optimum electricity generation.

How much does a screw turbine differ from a conventional turbine in terms of cost?
The difference is significant. A screw turbine requires less civil engineering works than a conventional turbine and thus costs less to install. In the long term, the screw requires much less maintenance and requires little energy to operate.

Do I need to install a bar screen?
No. While the screen openings on non-fish-friendly turbines are only 2 cm wide, the openings on the upstream screen of the Elléo scheme are 10 cm wide. Jams, small branches, stones, dead leaves and algae pass through the screen and flow into the screw.

Is a special scheme required to allow downstream migration of fish?
Again, no. Fish pass through the screen and into the screw unharmed. This has been proven by several studies conducted by Onema, the French National Agency for Water and Aquatic Environments.

What type of maintenance does the Elléo scheme need?
Aside from draining the gearbox and the hydraulic unit once a year, the Elléo scheme requires very little maintenance. The bearings are automatically lubricated. All you need to do is check the level of lubricant once in a while and replace the filter if necessary.

How efficient is a screw turbine?
More than you think! Its advantages include no fine screens, fewer pressure drops, no bar screens to be operated on a nearly daily basis and minimal maintenance. Overall, when all these factors are taken into account, the generation potential is at least equivalent if not greater.