Ady,

I've thought for years this is the way to go, the power density available will be much more favourable and the ultimate source from planetary movement is as reliable as that of the sun appearing each day.

Far and away better than wind turbines and other such weather dependent methods.

Brian.

This actually looks like a reasonable way to generate power. At least it is predictable years in advance, and if you have enough of them round the coastline should be fairly constant(unlike windmills).

Anyone know why the one on Strangford Loch is being de-commissioned?

Tidal turbines appear to be an obvious way forward for power generation. Over the last ten to fifteen years large well respected engineering companies have started work on the technology and then very rapidly abandoned it or sold their work to others. This would suggest that the concept has serious difficulties.

One possible difficulty is that sea water is about 900 times denser than air. This means that the static forces on a structure in a 10 knot tide would be about 13 times great than the same in a 100 mph gale. The dynamic forces from shed wakes etc which would amplify the problems.

One could sit and think about this much further which is what the "big boys" have done. Still it it is more likely to succeed than controlled nuclear fusion.

JA

[I assume that these are free standing turbines like wind turbines and not a barrage scheme. The latter has different problems and advantages].

Edited By JA on 29/08/2016 11:56:39

.

It certainly looks that way from the video that Ady1 linked

… What did rather surprise me is the [very slow] speed at which they appear to run.

MichaelG.

Andy Ash. I mis-read that as "Have the weight of the thing generate electricity whilst it gradually fails." A Freudian mistake perhaps.

Just a bit behind the French who have had the La Rance tidal barrier generating power since 1966!

John

As far as I can tell it does a bit of both depending on the state of the tide, according to this report by the British Hydropower Association. Still not bad considering how old it is.

John

As you say Adrian, the technology has been around for rather a long time. The Swansea Bay scheme or even possibly the full Severn Barrier would be excellent projects. Better in my opinion than getting the French and Chinese to build Hinkley C using an as yet untried type of reactor, which will without doubt take twice as long as thought to build and cost four times as much as estimated.

The Government just need to make some sensible decisions (no hope there then) instead of holding endless investigations, committees and enquiries. While they are at it they could stop HS2 and spend that cash on tidal power schemes (another pig just flew past the window).

John

Hydro electric usually runs on fresh water so the turbine blades have a different marine growth to deal with & i believe that they run quite fast thus throwing anything off before it can fasten itself to the blade

What will be a problem with tidal systems is the gradual build up of marine growth. These turbines run fairly slow so will not shed the slime etc once weed gets a foot hold it will greatly affect performance. This will happen mostly during neap tides.

There are no antifoulling systems currently invented that are safe for the environment that can be used & whilst the designers may have considered this i am sure it will be a major problem

Hi Rupert,

Am I right in remembering you used to be based in Lanson? I seem to remember seeing some sort of water wheel for a micro-generating plant that had a vertical axis in one of the the old railway buildings in Newport, many years ago.

' Course, I could be dreaming again…

Cobbs.

Here is my venture into hydro, this is a Francis turbine installed at a local farm here in Canterbury (NZ), it was imported from the USA, in 1879.  It has a head of about 16ft. 

Ian S C

Edited By Ian S C on 01/09/2016 11:12:09

Hello,

Yes, that was my workshop in 'Lanson'. We moved back to the family mill about 30 years ago, and now the old workshop is the main 'shed' for the 'Launceston Steam Railway'. Apologies for the delay in posting a reply, but I have been trying to stop 'Hinkley 'C' Nuclear Power Station in favour of renewables and grid control systems (without success I regret).

The turbine you saw in the workshop must have been running for over 30 years by now. Not quite sure which one it was, but there may be a picture on my web site http://www.evans-engineering.co.uk . I have been hoping to update the site for sometime, but not enough hours in the day.

As for steam things, I had hoped to salvage the two enormous (30 inch bore) 'Cornish' type steam pumps (JE&S) from Manton Colliery a few years back, but I gather that the shaft has been filled in and that there is a B&Q on the top of the site and the pumps are 300 feet below it! Maybe an archaeological project in a few hundred years time will dig them up!

Small-scale hydro has been swamped by an enormous amount of 'red tape' that grew out of Government grants and 'Feed-in Tariffs'. Now the subsidies are almost gone and one is left with just the 'Red Tape'. Anyone out there still interested in building things?

Rupert