As part of the early stages of the project, a consultation was commissioned to assess the site and to recommend the most appropriate technology and layout. The outcome of this was a recommendation to install an Archimedes Screw on end of the Weir, adjacent to the existing Ludford Mill.
The suggested size for the turbine was 30kW. This will generated enough electricity to supply about 40 households (about 150,000 kWh per year).
The Archimedes Screw is recommended because it is the most fish-friendly design of turbine (fish can pass through without suffering any harm) and this design of turbine suffers least from getting blocked by debris. A great deal of work has been done by an organisation called Fishtek to demonstrated this to the satisfaction of the Environment Agency. Another advantage of the Archimedes screw is that because fish do not need to be excluded, it does not need a very fine screen at the intake, and therefore is much less prone to becoming blocked with debris than other forms of turbine.
An Archimedes Screw turbine comprises a large helical steel “screw” (in our case about 2.5m in diameter) rotating at a very slow speed in a concrete or steel “trough”. The consultant we are using for the design work is Mann Power Consulting, who have installed many of these around the country which you can see on their website.
In our case (see picture on the left) the screw will be contained inside an enclosure which will be built of the same material (stone and timber) of the existing buildings, and the screw itself will not be visible. The enclosure will also provide sound insulation so that noise levels will be kept very low.
More detailed draft plans can be downloaded from the Download page.