DIY Electro-Waterwheel

In most of the cases mentioned in this thread the infrastructure to manage the water was already in place before the generator was placed there. There was an existing weir or mill race to supply, and more important, control the head of water. There was little expense to modify the river flow.

These generators will have been designed for a fixed head of water and amount of water flowing though the turbine/screw etc. A weir can control the head water as long as the weir is wide enough to cope with the variation in river flow. There is a good reason why weirs tend to be built on the widest parts of rivers. The example I linked to on the river Teme is situated at the side of a very wide weir, 200+ metres(?).

Consider also the sites of old water driven mills. Many were not situated in ideal places for commerce or close to villages or farms but in the limited places where they could actually be made to work.

What some are now advocating is that rivers should be lined with 10s or

Some river authorities are actually removing (defunct) weirs for better river flow in flood conditions and/or for environmental reasons such as fish migration.

On the River Wey, a fish "ladder" has been built round one weir. This, of course, has been done in Scotland with some of the hydro-electric schemes,

In the early days of power generation there were quite a few small hydro stations some private on a country estate followed by some installed by early pioneers in electrical generation for public use such as the Christie Brothers of Chelmsford who set up stations in the South West and elsewhere .The odd one is still in place such as Mary Tavy and Tavistock but the their output is very small in the grand scheme of things . The one at Chagford which ceased generation in the 1990’s was up for sale a couple of years ago.

This substation in Ringwood Hants marks the location of a hydro plant that once stood there,

Built in 1925 , the Avon there is a reasonably flowing river but they found the installation could only supply 36Kw so diesel sets were added. The derelict turbines remained rusting till the building was demolished in the

There may be the odd location where a station could be installed just to supply a small community if they wanted to disconnect themselves from the grid and yes every little helps but in a commercial setting you would barely cover the wages of people maintaining the equipment and keeping the water channel clear of debri.

GH

And of course we've all seen on TV salmon getting up natural weirs.

As a final year electrical engineering apprentice, I had the job of test synchronisation of the 500kW generator set mentioned in here:-)

The Wey Navigation has recently had a very expensive fish ladder installed in parallel with a weir.

John

Now consider how much environmental damage will be caused by messing the river flow up. No more shallow fast flowing bits for a start.

Andy

I am curious as to whether sufficient numbers of wind turbines will be built to begin to affect wind patterns on a large scale, which will of course cause..... climate change.

Higher temperatures mean generally stronger winds, so perhaps this is a good thing.

Dave

But a lovely calm pike pond gets created...

Despite all the doom and gloom climate temperature warnings we have had in the past week wind seems to be producing bugger all electricity recently. :)

But full of weed an algae that will clog the filters and perhaps the generating mechanism - especially with run away temperatures caused by climate change.

Indeed, we mustn't forget the hockey stick.

There are no runaway temperatures caused by climate change, outside of the Guardian...

In fact there never have been. There may be, in 600 million years time, when the Sun has heated up enough to boil the oceans and kill all life, but until then ...

And don't anyone say that the CO2 levels have never been this high, because that's bollocks too.