Archimedean Screw Hydro Turbine – Fish friendly generation

Archimedean Screw – Fish-friendly generation

What site?
·  Fall (head) of 1m to 10m
·  Flow from 100 l/s to 10,000 l/s

Why an Archimedean Screw?
·  High level of efficiency maintained across a wide flow variation
·  Environment Agency approved
·  No need for expensive fine screening
·  Robust, simple machinery – low maintenance
·  Minimal construction work necessary
·  Dry running and debris in the water flow do not harm the machinery
·  No complex control system required
·  Design life: 25 – 40 years

·  Achieves an efficiency of up to 87%
·  ‘Water to wire’ efficiency of 77%
·  Highly efficient down to 20% of maximum flow

Steel Trough

Steel Trough

Fish friendly
Extensive fish passage tests have conclusively demonstrated that the large water chambers and slow rotation of the Archimedean Screw allow fish of all sizes, and debris safe passage through the turbine. As a result, the Environment Agency has agreed that no screening is required. Literally thousands of fish passages have been monitored and recorded using underwater cameras at the intake, inside the chamber of the Screw itself and at the outflow to assess the effect of the Screw on salmonids (including smolts and kelts), brown trout and eels. The trials looked at fish passage across a broad spectrum of sizes and turbine speeds, possibly the most impressive of which was the safe passage of a kelt measuring 98cm in length and weighing 7.6kg. In addition, behavioural and migrational patterns across the species have been shown to be entirely unaffected by the turbine. The implication of these findings is extremely positive for the economics of micro-hydro. Sites previously written off for hydro development owing to fish protection issues can be revisited, and the cost of installation for an Archimedean Screw turbine will be significantly reduced by the requirement for only minimal screening.

Fish friendly Archimedean Screw hydro turbine

Fish friendly Archimedean Screw hydro turbine

One year on -a customer testimonial
Mark Simpson, owner of the River Dart Country Park at Ashburton in Devon decided to install an Archimedean screw to replace an old Kaplan system which had been beset by problems in the past. “The screw suits this environment so well, particularly given the vagaries of the River Dart and the way that it copes with the debris and leaves which were a problem with the old Kaplan system.” The new system produces a maximum of 48kW, more than enough to run all the visitor facilities on site, Holme Park House (used as a conference centre and wedding venue) plus two visitor bungalows. “We have been running through the summer at pretty near full capacity (45-48kW). During the dry spell it did drop down to 35kW, purely because of the limited amount of water we could take out of the river and down the leat.” Mark is a great advocate of the Archimedean screw as a satisfied customer: “The power output is more than I budgeted for or envisaged in the planning stages and I’m delighted at how the whole scheme has come together”.


  • Dave Jordan says:

    Hi Mary,

    Well done on your first blog post, we will subscribe to your RSS feed and keep up to date with all that’s coming up in the eco world.



  • Frank Heller says:

    I am considering this device as another ‘fish friendly’ component in small hydro installations.

    We need pricing and installation designs; as well as a ‘certificate of approval’ from an independent fish biologist as to both down and, especially up stream migration.

    The fish species of concern are salmon runs upstream…large fish and smolts downstream; alewives both up and down; and eels up–large, and down, elvers–tiny.

    It appears to be impervious to icing up? and small debris.

    Do you have output data for ROI calculations.

    Ironically I found out a friend makes wooden bearings he says were used in some kind of Archimedes screw somewhere…I then got a sales pitch for wooden bearings as more durable than metal for underwater applications and I made one back to sell him lignum Vitea belt wheels from an old sawmill he could recycle.

    Anyway, I think, depending upon costs and fish habitat issues this could be an exciting reinvention of the wheel.. circa 1,000 B.C.??

  • Greg Allen says:

    This looks pretty impressive. The low rpm and only 1 or 2 leading edges render it very fish friendly. If operated in reverse it could potentially be used as a fish lift to pass migrating fish upstream. This would require attraction flow, and a crowder that will add to the costs. I’m also interested in the ROI.

  • Zeno Winkens says:

    Hi Frank,
    great product, I hope I’ll have a client that will need one soon.

  • Ben Mehuwa says:

    very interesting product, would like to know more about it to see how it can fit into my environment.

  • karan dudhane says:

    it really helped me in my project. thank u so much!!!!!!

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