ELECTRICAL POWER

New Zealand Times, Volume XXVIII, Issue 6052, 9 November 1906, Page 3

ELECTRICAL POWER

THE HUKA FALLS. FUTURE POSSIBILITIES. Air P. S. Hay, Enginecr-in-CMcf to the Public Works Department, in bis report to tho Alinipter on tin; utilisation of water power, remarks: — At Huka there are two plans for dealing with tho development of the available power. First, a short channel may be cut on either side of the river to take the whole river low-water How to arorios of turbines located as near tho ■edge of the pool below the fa!lei as may bo deemed safe. The present channel would be blocked snfbeiently to send tho necessary amount of water -at all times to the turbines, and provision would bo made for tho escape of tho surplus water at periods of high flow, or of the whole of the water when the turbines were not at work-. No storage of the- lake waters) would ho attempted. Turbines with vertical shafts would bo necessary unless excessive excavations were amide. The area is too limited to admit of tho ready neo'of turbines with horizontal axis. In addition to the channels, the works required would bo a concrete wall to protect the power-station from Inundations, sluice-valves and gear, concrete and steel pipes, and chambers and tail-races cub below the surface ol wafer in the pool of sufficient sectional area to take tho water freely from cbo draught-tubes. The power obtainable would bo about 22,000 h.p. Tbirt eohemo completed with trans-mission-lines to serve tho Auckland district only would coot about £015,000; but the whole need not bo carried out at once —about half, costing übo-nt £325,000, could bo done first, and additions made as required. Tins scheme would hoc attempt to control the flow of water in the Waikato River, and perhaps less than the average minimum flow would have to bo accepted at timed owing to winds affecting the outflow of Lake Tav.po. CONTROLLING THE WATERS. Secondly it is possible to build a dam across tho river-valley just above tho falls, and thereby control the waters of the lake. This scheme need nob bo taken as independent of the flmt one, but as a final _ development thereof if tho power-station in tho first place in put on the left bank oftho river. If only the first development wore to bo final the best position for tho power-station would bo -an tbo right bank of the river, but there is too little room hero for tho larger power-station required if the water is all conserved. The power's tnbi cm being put on the left bank of the river at first and all works being suitably designed the dam could bo completed at any time, and power developed up to 70,000 to 80,000 b.b.p. os may bo deemed necessary, or continuous working 38,000 b.b.p. would bo the probable limit of power from the Waikato flow at Huka. The cost for 70,000 b.p., all power delivered at Auckland, would be about £1,600,000. Tile cost of tho dam would not likely axcoed £25,000. The Huka scheme id one tor which the development may ibo continuous from 10,000 or 12,000 h.p. to, say, 80,000 h.p., without waste In any way or sacrifice of previous work. Part only of the canal-excavation might bo saved by complete development at once, but Lilts is so small a part of tbo total necessary expenditure that it need not bo considered. Tile fall available without a dam would bo about 50 ft., and with tho dam about 04 ft. The turbines and generators would all bo designed to Work at maximum efficiency for_ the •64 ft. head, so that if the additional development wore made before the first 'units’,.wore out they could be advantageously used. The low fall available at Huka will entail much more expensive turbines and generators per horse-power than in tho case of higher falla. This with tho long-distance transmission will_ increase tbo cost of power obtained from there.

For tho completed scheme, 38,000 b.p. at Huka, the east for any large continuous supply of power (8760 hours per year) ihay bo taken as £6 10s. per horse-power year menstured nt the consumer’s meter at Auckland, and for part-time supplies in smaller quantities higher rates, and for a partial scheme tbo rate would have to be 15 per cent, higher at least. GENERAL COMMENTS. SOAIE DEDUCTIONS. Partial developments may bo made to start as shown below:—

The larger part of the power now in in the various districts is only worked eight hours per day. Tho Kaitnnn schemes would not he rery favourable ones for partial development, as the cost of the fivll-power conduits would heavily load tho partial scheme. It is not clear that any scheme there would remain long partially developed, as a largo amount of power is used in tho Auckland district. Tho Huka is the heft o'f all schemes for partial development at first, and any scheme can he carried to full development with hardly any loss. Tho Hutt scheme should he completed in tho flint instance. Coleridge is a scheme that is very favourably conditioned for partial development; and subsequent completion in successive stages as tho demand for power justifies. Opihi, on account of tho cost of the dam and tho expensive conduit through tho gorge, would not ho a very favourable scheme for partial development. Tho Teviot scheme is one where tho conditions are fairly favourable for partial development. In partial developments it will bo essential, to avoid future. loss, to make tho conduits full cine at first, as they cannot subsequently ho enlarged without stoppage in working for a cont'jdorablo, period. v COST OF PLANT. Tho cost, so far as electric plant is concerned, in the above estimates is for tho most, part based on prices obtained by tho consulting engineers in England from manufacturers of high standing. It will now ho the best course t a send full information to the consulting engineers for the colony in London, 'and, through thorn, and on

conditions to bo laid down by them, to obtain from the loading companies manufacturing electric and hydraulic plant prices for tho plant required in each case. Tenderers would submit offers for tho types of their own Otandard design of tivrbiifes, generators, and other machinery and appliances. It would he advantagermw to ■■elect one type of machinery for all plants if possible to insure uniformity throughout as much as possible: the consulting electrical engineers in London to advise on offers. There are two technical conditions which influence tho cost of transmis-sion-lines—the frequency of tho alterations and tho voltage of transmission, low frequency and high voltage being favourable to economy in the tiansraission line. Low frequency increases (lie cost of the transformers, and greatly increases the capacity of a line for transmitting energy. Ac* there are practically no restrictions bore as in other places where power-installa-tions have keen made, the most favourable frequency and voltage should bo adopted. Until a tranomission-linc is actually located it is not possible to give more Mian a general average value for tho cost; forming roads, clearing bush, etc., may in some cases increase the cost very materially, but generally very little bush would be traversed. In meat of tho schemes tho cost of hydraulic works—weird, dams, conduits, and pipes—much exceeds the cost of tbo electric plant. A somewhat full investigation into tho probable costs at which power can be got from many of our power nehemes appears to show conclusively that it will be possible to supply power at relatively low rates —sufficiently low to insure . a certain sale for all power which at present it lappears prudent to generate. THK SWEDISH PROCESS.

A considerable amount of Information has been obtained through the High Commissioner about tho process .low at work in Sweden for the manufacture of nitrate of-llmo fertilisers. Phis information ban been got direct from one of the Inventors, Professor Birkcland. Ho claims that the process is nuccessful, and that about 0.4 of a ion of nitric aoid may te got per horsepower year, giving about 0.52 of a tern of nitrate of lime per horse-power year. From Manapouri and Te Anau Lakes, diverted to Mio Sounds, about 600,000 tons of nitrates could be made a year, at present rates worth £13,000,000. Employment would bo given to about four thousand men. I’ho expenditure required would bo about £10,000,000 to supply tiio electrio energy; tho cost of the works and plant for the manufacture of the acid X have no information about at present. Tho worlm would be situated •near or alongside deep water. Similar factories c-oidd be -established at other points on the West Coast Sounds and at numerous other places—Hnuroko, Lake Hawon, Tekapo, Rotorua, Waitmromoana. It has been stated that vithin tho next few decades the demand for nitrate fertilisers will greatly increase, while tho only natural do-ne-sit at present known is being rapidly worked out- Alost of the other by dro-electric industries are of lessor apparent importance than the nitrate one, and tho perfection of the process ,o insure its successful commercial working would make the full development of so many power schemes possible in Now Zealand with every prospect of profitable returns being obtained -.here from.

COST PER HOR-SE-POWER. To illustrate tho amount of money it is thought it „ may be profitable to spend on tbo development of waterpower, out of 1,250,000 h.p., the estimated resources of Norway in waterpower, concessions have been already granted for tho development of 530,000 h.p. The estimated cost for development is stated to be £55 per horsepower—a high figure; and unless it includes more than providing the .dro-electric works, New Zealand power, schemes would appear to be more easily developed than Norwegian, the cost per horse-power for the schemes herein dealt with varying from about £2O to £3B per horsepower. Information has been obtained from England about suction gas and other planta likely to compete with hydroelectric power. Seeing that immense developments of electric power are now in progress at Niagara, it is a fair conclusion that for general industrial supplies of energy gas-engines’ as motive power are not at present able to supplant, electric power when generated from economic water-power schemes.

- Power and Cost. Power and Coat. Power now used in Districts to be served. H.p. H.p. £ H.p. 76,000 750,000 18,000 590,00fj) 87,000 89,0 r ;0 790,000 15,0'>0 0,000 12,000 420,000 390,1001 10,000 kau n.nno 470,000 17,000 170,000 j 33.000 i 440,000 ll.Qi 0 310.000) ■Coloridca .. ;29,000 700,000 14,601 440,009 f 21,000 ifi.nio 610.0')0 in,ooo Tovlot 27,000 10,500 400,000 18,000