WORKING IN A DELICATE ENVIRONMENT

ARE WATER TURBINES HARMFUL TO FISH? WE COMPARE SOME DESIGNS

Have you ever paddled a canoe or a similar small boat? If not, you have probably seen someone else doing it, either in real life or in a film or a television programme. The canoeist uses the paddle to push the water backwards and the water then automatically (i.e. following the laws of Physics) pushes the boat forwards. In other words, a form of power is created by the force of the water on the paddle.
In such a situation, the work done by the paddle is very similar to the action of the blade of an old-fashioned waterwheel - an item that used to be very common in the United Kingdom but is seen only very rarely these days. A waterwheel stands upright in flowing water, usually a river, and it looks just like a miniature version of the sort of ‘big wheel’ that we often see at fairgrounds and other popular outdoor events, but the seats that swing have been replaced by big blades (i.e. flat boards) that are fixed into position so that they provide resistance to the water that flows against them. As with the canoe, the force of the water causes the blade to move - and the wheel goes round as a result. Power is once again created by the force of the water on the blade.

It is obvious that the blades cannot move any faster than the water. Therefore, the fish etc. that are in the flow can easily pass through the wheel by swimming in the water that fills the area between any two of the blades. That short journey takes them only a very small amount of time (possibly less than one second), so they cannot come to any harm.

However, an Archimedes Screw Turbine is not as harmless to fish etc. as a waterwheel is. This type of turbine consists of a huge screw that fits exactly inside a long tube or cylinder that cannot move at all. Its action is the reverse of turning a screw to make it bore into a motionless piece of wood. The screw is itself held in position but it is made to turn by the water flowing through the cylinder. Fish etc. are at risk of receiving some slight damage if they accidentally come into contact with the outer casing as they swim in the channel of water that is formed by the thread of the screw. In addition, it can take a number of seconds for them to make that journey through the turbine.

The Hales Turbine is just like a waterwheel that has been tipped over onto its side and placed completely beneath the surface of the flowing water. Its special design allows the blades to swing freely for a few moments as the turbine turns but their front edges are well-rounded and they move very slowly, so any fish etc. can come to no harm as they pass through - a journey that takes them only about one second.

A very common type of turbine is the one that looks a bit like a ship’s propeller or a windmill. In fact, they are often called “propeller-type” turbines, and they usually have only a few blades (and sometimes only two). They are positioned completely beneath the surface in such a way that the water flows through the gaps between the blades - just as it would flow through the wheel of a bicycle if it approached one from the side. The blades are angled or twisted slightly so that they are pushed around by the water and do not simply obstruct the flow. However, they cut across the flow - so they are obviously a danger to any creatures that happen to get in the way, as their action is similar to that of a big knife coming down with great force to chop a piece of meat. For best performance, the front edges of the blades are often made sharper than those of the Hales Turbine so they can cause even greater harm to any fish with which they come into contact. That danger is obviously a very big problem when huge “propeller-type” turbines are used out in the open sea, as whales etc. can suffer some harm if the machinery is not surrounded by a form of barrier that allows the water through but keeps the creatures out.

FISH KEEP NET FOR GREAT WHITE SHARKS !!!

This fish keep net maybe big enough but has been specially made to catch any small fish or eels that may pass through the ducted Hales Turbine prototype screens while it is being tested on the River Thames. This is just one of the Environmental Agencies special conditions to be met, to comply with the strict regulations to protect the river and its wildlife.
The net has be modelled on a similar unit fitted to the Torcedo water turbine during trials but has been made extra long to allow the net end to be raised and checked frequently during testing to prevent debris harming any fish.
New Datum Torque Sensor equipment has been fitted at the test site and a 24/7 water flow recording started of the Flood and Ebb tidal flows at the site, to help build a picture of the year round flows in this area.

NEW TIDAL TURBINE TESTING PONTOON IN THE THAMES

After a great deal of work and effort by Davrek Engineering Ltd of Eastbourne, East Sussex to build, the students from the Faculty of Engineering, Kingston University, London to assemble and USM Ltd at Trinity Buoy Wharf to deploy, the new ducted form of the Hales Turbine has been installed on the Thames. We are now ready to start the detailed development testing now that Environment Agency consent for the testing has been granted.
There is still a great deal of work to be done, fitting handrails, walkways etc and operating and test equipment to the turbine but we expect to be testing within the month.

FORWARD TO NEXT STAGE OF TESTING

With generous help from USM at Trinity Buoy Wharf, the next stage of testing will be greatly helped by the construction of a new catamaran type pontoon complete with a special ducting system that will contain the original Hales Tidal Turbine prototype. This new pontoon will allow turbine testing and development to take place under closely monitored conditions. The Hales Turbine has entered the Environment Agency's Hydroelectric Power Scheme, the first major hurdle towards MCS the ( Microgeneration Certification Scheme). These prototype trials together with the new test tank being built this summer will be used to prove the fish friendly nature of the patented Hales Turbine so it could be used for micro generation in run of river locations, together with Low-Head Archimedes Screw type generators, currently the only other fish friendly design.

SOME GOOD NEWS FOR PROJECT

As the team work towards testing and developing the Hales Turbine design with the prototype testing, the new Race Track type test tank being built this summer and the detailed computer Fluid Dynamic work being undertake, the good news is that the first of several patent applications on this renewable energy tidal turbine has been granted after five years in the system. New patent applications are being added all the time as testing shows the way forward.

Paul Hales
Director

Hales Energy Ltd

Starting Spring 2011, Hales Energy Ltd will start construction of a new special Race Track Type water flow test tank in East Sussex which will be used for testing new blade profiles and configurations together with various ducting profiles to suit a variety of applications. Specialised torque sensor and water flow equipment will be installed in the tank for testing to a certification level and also aid in preparation for the necessary fish friendly trials this turbine will need to undertake.

Meanwhile, the design work on the one metre prototype will continue at Trinity Buoy Wharf. As well, we shall be carrying out a detailed long term study of the tidal water flows in that area with highly accurate water flow test meters purchased from Omini Instruments which are both doppler and rotational types and can be hooked up to computer software for later analysis.

The new light weight Carbon Fibre Power Blades have been fitted to the prototype and not only lighten the whole device without a loss of strength but look really smart.
Many thanks to Dr Tim Swait, along with Dr Simon Hayes, at the Dept of Engineering Materials, Sheffield University, for arranging these special blades, hopefully the feedback to Tim will help the advancement of composites use in marine energy.

Paul Hales, one of the Directors of Hales Energy Ltd will be working full time at the new test tank location as from April 2011, which should speed up the testing and data collection, with the hope to have results completed by the autumn 2011. Then to design varies sizes of complete micro generation units for the commercial and domestic markets. Research will still continue into designs for ocean current and large scale tidal applications.
Computer Fluid Dynamic modelling has already taken place for the design of a special ducting system to use in conjunction with the Hales Turbine to boost water flows past the blades, this to allow deployment in sub 2.0 m/s flows such as many areas of the English Channel etc.

HALES TURBINE PROTOTYPE ARRIVE AT GREENWICH

The Hales Turbine testing and display pontoon has arrived at Trinity Buoy Wharf, opposite the O2 Dome, where it will be moored on the inside of Jubilee Pier while it is refurbished and extra equipment fitted.