TIDAL ENEGY.

Gisborne Times, Volume XXIX, Issue 3389, 2 December 1911, Page 3

TIDAL ENEGY.

WEW L3GHT UPON AN OLD

PROBLEM.

CONSTANT POWER

Colonel. E. N. Maude, C. 8., late R.E.. writes as follows in the “Standard” :

When Sir William Ramsay delivered his prophecy as to the approaching exhaustion of our mail supply and the impossibility of harnessing the tidal cure-nts to t-a-k-e the place of coal ns a source of energy, lie was speaking strictly in accordance with the book, hut it was a 'book that was some few months out of date. Some twenty years ago every engineer had “tidal power” on the brain, and I was asoeiated with a very prominent electrician in the consideration of several schemes, but twist and turn them as we might, we always rail up against a fundamental difficulty, viz., that the intrest on the first cost of construction invarinab'y wiped edit the ultimate saving on the fuel bill. The cost of construction, however, is divisible into two separate headings, viz-, the cost of impounding enough water to give the required power whilst the tide is running either out or in, and the cost - of accumulating enough power (either electrically c r otherwise) tomeet the requirements of the- consumer during the periods' of slack water, when there is no difference of level between the tide and the water in the reservoirs. This is really the crucial point of the whole problem, for civilisation cannot readjust itself to work by tidal time.

A solution of the first portion of the problem came to me some years ago, at once simple and inexpensive, but though it reduced the expenses of one installat’on enormously, the second part still stood in the wav, viz., the accumulation of power necessary to meet the peak of the load when it happens to coincide in time with the period of slack or high tide. The solution of the second part, however, came to me quite recently in a rather eurioust manner. I had often had occasion to travel between London and a coast town, backwards and forwards, and had- noticed that if it was high' water in the Thames when I crossed it on my outward journey it was always high, water at the other place- .at the time of my arrival. Of course, T was always well aware that the time of high water varies all along the coast—every yarflitismcn knows (that- J}a-ct—-but its significance never struck me until on that on day, with the tidal scheme in my head, it flashed upon me that I had found the explanation of all my difficulties. LINKING UP.

If it was high water, sav, at London Bridge at 2 p.m: and high water at my destination about sixty miles awn- across country at about 4 p.m.. it followed that when the current was slackest at the former place it. was running strong at the latter. I had only to put down a plant at each place big enough to feed both places and connect them by an electric cable to- secure a constant output of power, without the need of any accumulators or other stc-rage arrangements at all. I went buck to my estimates and caonverted the idea into pounds, shillings, and pence, and found that whereas in the best of our previous projects the capital outlay for each nominal horse-power came to about £7O (the interest on which exceeded the saving in the coal hill), under the new conditions tho whole excess of prime cost compared with a steam plant came down to about £lO per horse-power, the interest on which, say 14s a year, was small as compared with the cost of coal and stokers’ wages—say £3 for each horsepower per year. To utilise the tidal energy now running waste all round our coasts, all we have to do is to take the map of these islands and couple up -the great estuaries opposite . one another—Severn and Thames, Doe and Humber or Wash, Forth and Clyde, and so forth. Tho first would supply cheap power to the Birmingham and London districts, tho second to Lancashire and the West Ridin" the third to Glasgow and the Scottish manufacturing districts, and though it- may not be possible to locate’sites capable of giving more than 100,000 horse-power continuously to each (at least. I will not- answer for more), the diminution of the drain on our coal-fields would ' very, appreciable indeed, and would certainly render any rise-of wages to the miners exceedingly problematical.