There's one a few yards down the road from me, others in Dorset yet more in the New Forest. There's even one on an island in Poole Harbour.
The presence of elaterite and Blue John in Derbyshire indicates that there could well be decent quantities of oil under the Peak District.
You appear to have missed the fact that there are still coal measures in the UK that could be extracted by opencast or adit mining. Not to mention peat reserves. You also seem to have a hysterical perception of the problems of mining.
Modern turbines operate at about 90% mechanical efficiency, even at the beginning of the 19thC turbines were achieving over 80% mech. efficiency. By the end of the 19thC turbines had hit the 90% figure.
Pitchback waterwheels achieve 70-80% efficiency, overshot wheels up to 70%.
On Wed, 11 Oct 2006 14:45:03 +0100 someone who may be Tony Bryer wrote this:-
Having read to the end of this little sub-thread I have a few comments to add.
Small turbines are being installed to make use of such flows of water in various places. Water companies have led the way on this, presumably as a source of additional income.
There is great potential for run of river and low height hydro generation. Many existing buildings could have turbines installed and much of the civil engineering would only need relatively little work to bring back into use. Obviously this will not generate all the electricity for the UK, but every little helps.
The idea that big is beautiful dates back to the time when machinery involved humans standing over it to keep it going. This has slowly become unnecessary over around 80 years. By ISTR the mid 1980s the Hydro-Electric Board was controlling all the hydro stations in its patch from two control rooms. Humans only visited the small ones occasionally.
Another reason for big is beautiful thinking is to do with burning the least fuel to make the most electricity. However, that line of thinking is not productive when the fuel costs nothing (though arranging to use it is likely to have a high capital cost).
On Thu, 12 Oct 2006 21:51:24 +0100 someone who may be Matt wrote this:-
The conversion of Anglicised spellings to something more "Welsh" started in the 1970s and was largely complete by the 1980s. Some complained about the cost, but there is always someone complaining about the cost of anything.
On Wed, 11 Oct 2006 08:08:53 +0100 someone who may be Andy Hall wrote this:-
Feel free to look up the survey reports. I can't think of one I have looked at where the questions used and any background information provided have not been in the report.
I still haven't seen a trustworthy source for the efficiency of water wheels and there is a complication because the output may not need to be constant full power. When I looked at making use of a small mill pond for running a heat pump for a local firm I made a few enquiries and the capital cost of the civils looked too great but a breast shot that exhausted the water contra to the rotation, as a pelton does though technically the water should drop off with not velocity, looked the most efficient water wheel. This same design was used by that scrapyard wars bloke in a recent tv series.
At that time Guy King suggested Peltons were regulated by a pintle type jet which maintained water velocity but varied its massflow. Looking at the graphs provided by British Hydropower Association it looks like this gives the Pelton a good, flat power characteristic from 20% up to full power with conversions up to 90% and never below
80% in this range. Head required is above 100m for a Pelton. A simple propeller type is very peaky reaching 90% conversion at full power but falling almost linearly to zero power at 40% flow. Kaplans, which I think are variable pitch propellers, approach the pelton curve and exceed it at full power. Francis, which are a sort of centrifugal fan run with the flow from outside to inside, are half way between simple propeller and Kaplan but still over 70% conversion over half the flow range. These latter are low head devices but minimum head quoted is
3m, about 10ft. I'd guess you would only look at a water wheel at heads lower than this. The civils and equipment costs for the low head devices reflect their size and massflow requirements.
So given a high head and a good stream there will probably be a few places, probably commercial properties like a hotel, where a constant but small proportion of the flow can be unobtrusively be extracted by a hidden leat and spillways, to generate an economic electricity supply. Given a grid connection a 4.5p/kWhr kick back and carbon trust funding may be an incentive.
On Fri, 13 Oct 2006 11:36:09 +0100 someone who may be AJH wrote this:-
Water wheels look quite attractive compared to a metal casing, inside which there is a water turbine. The look may be desired, for example as a means of drawing people into a venture and this can be a reason for building one.
However, as a means of extracting power from water there is a reason why turbines took over, they get more out of the water then a wheel.
|On Fri, 13 Oct 2006 11:36:09 +0100 someone who may be AJH | wrote this:- | |>I still haven't seen a trustworthy source for the efficiency of water |>wheels and there is a complication because the output may not need to |>be constant full power. | |Water wheels look quite attractive compared to a metal casing, |inside which there is a water turbine. The look may be desired, for |example as a means of drawing people into a venture and this can be |a reason for building one. | |However, as a means of extracting power from water there is a reason |why turbines took over, they get more out of the water then a wheel.
At high heads!
Just seen a place where a proposal for a reversed Archimedean Screw driving an electric generator is at planning permission stage.
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study with diagrams at:
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looks to me as a very good way of harvesting power from the low head high volume which they have there. They have a ?3? ft weir with a fair sized river flowing over it.
Did you fail to read the earlier observation about cheap coal imports? How can miners at UK wages compare with either rock bottom waged Polish miners, or strip-mined Australian coal?
The short answer is that you don't have a clue.
BTW, did you know that the "exhausted" oil wells around the world still contain 60% of their oil? Current extraction technology can only extract about 40%, all it takes is for some bright spark to improve on that and it's crisis, what crisis?
The village from which it takes its name was Dinorwic on Ordnance Survey maps for a long time and due to the vagaries of the OS system lasted several years longer than other prominent name changes such as Cader to Cadair and Dolgelley to Dolgellau.
He's wrong even if one makes allowance for hyperbole. An overshot waterwheel is not much less efficient than a Pelton wheel, it is less efficient. A pitchback wheel (a form of overshot wheel) gets close to the efficiency of a Pelton wheel.
Estimates of water wheel efficiency given in "Stronger Than a Hundred Men: A History of the Vertical Water Wheel", Johns Hopkins University Press 1983 are:
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