SUPPLY OF POWER

Taranaki Daily News, 26 October 1921, Page 5

SUPPLY OF POWER

INCREASING THE OUTPUT, SURVEY RECOMMENDED. BIGGER TUNNEL ADVISED. GOVERNMENT ENGINEER’S REPORT, The Minister of Public Works has received a report from his electrical engineer regarding the possibility of augmenting the water supply to the hydro-electric power station at New Plymouth. His general conclusions are that for the purposes of a local supply to New Plymouth and the surrounding districts a further survey and investigation of the Waiwakaiho and adjacent streams is desirable, and that the council should favorably consider the completion of No. 2 tunnel to the larger size.

The preparation of the preliminary proposals for extensions would cos* about £4OO and take about 4 months.

(Special to Daily News.) Wellington, Last Night. The report of the Public Works engineer (Mr. Kissell) states: “I conferred with the Borough Council and their consulting engineers as to the possibility of augmenting the water supply in connection with the hydro-electric power station. I was shown over the works and the various points in the basin of the Waiwakaiho and adjacent streams by Mr. Blair Mason (consulting engineer) and Mr. R. H. Bartley (borough electrical engineer). “As the result of my investigations it is evident that a storage basin can be obtained on the Mangamahoe, one of the small tributaries of the Waiwakaiho, and that storage basin can be supplied with water from the Mangawarawara and other streams in the Waiwakaiho basin; also from Mangorei and possibly the Kiri stream, outside the present Waiwakaiho drainage area. Probably, also, additional alternative storage basins could be obtained on other tributary streams of the Waiwakaiho. POWER AVAILABLE. “It is. impossible to put a value on these streams until a survey is made to disclose the amount of storage made available, to locate the routes of the best stream diversions, and to determine the nature of the provision to be made for riparian rights. The periods of drought are of comparatively short duration in Taranaki, and that even on the comparatively low heads available, additional storage would be of considerable value, particularly if that storage is also supplied by extra water outside the present drainage area. The minimum flow of the Waiwakaiho is given, as 150 cusecs, which at the works under construction will give 6000 horse-power on a 45 per cent, load factor, or, with the storage now proposed, varying amounts up to 9000 horse-power, dependent upon the length of the period during which the river remains down at its minimum.”

Six questions were submitted to Mr. Kissell. The first question was: “Does the nature of the country on the Upper Waiwakaiho appeal to you as being worthy of a survey for hydro-electric power purposes?” —The first part of his report gives the answer to that question, and he adds: “I consider it worth while to make a survey to determine what storage is available.” TIME TO MAKE SURVEY. Second question: “What will be the' amount of storage necessary on the available heads to produce continuously 4500 horse-power; and do you think the available streams will supply this quantity?” Answer: “To prod-ice 4500 horse-power on the available head would require 225 cusecs, and I think this amount can certainly be made available if the additional storage is provided.”

Third question: “Does it appear to be practicable to develop this amount of power at a figure that it could be sold at say £3 per kilowatt per year, at a load factor of 100 per cent., and pay expenses?” Answer: “This can only be answered after a survey and estimates have been prepared; but from general appearances and the nature of the work I would scarcely hope to obtain power at such a low rate as £3 per kilowatt per annum.”

Fourth question: “From your experience in this class of work, how long approximately do you think it would take for the necessary survey and estimate to be prepared ?”

Answer: “The amount of work to be done is somewhat indeterminate, and many points have to be investigated, any one of which might influence any of the others. Preliminary proposals could, I think, be submitted for about £4OO in four months' time. This, of cou.se, would not include final surveys and working drawings.” SIZE OF THE TUNNEL. Fifth question: “The present tunnel is designed to carry sufficient water to develop 9000 horse-power, with a loss of 8 feet. With a minimum river of 150 cusecs flowing, and with the storage available full, this is sufficient to develop 9000 horse-power on a 45 per cent, load factor for 10 days. Should the river flow continue on its minimum longer than this period the output of the scheme is reduced to 6000 h.p. approximately, on a ‘45 per cent, load factor basis. Under the present circumstances,- and any others that may occur to you, including the possibility of supplying larger amounts of power for short intervals, what are your comments re the size of the present tunnel?” Answer; “The question of the size of No. 2 tunnel is one of the council’s chief problems at present. Part of it has been excavated and lined 9ft. 2in. in height, but is now being excavated to suit an Bft. lining, and there is a difference of opinion on this. With a load of 6000 h.p. the larger size means a saving in load of 2 feet as against the smaller size (8 feet). This loss is, of course, nt the full load, and equivalent to 48 h.p. At 9000 h.p., for which the work was originally designed, the difference in head is equal to 4 feet, which, with the large quantity of water involved, is equivalent to a loss of 144 h.p. when, the plant is fully loaded. In view of these facts, and the answer to No. 1 question, that there is a prospect of increasing the power even beyond 9000 h.p. on a 45 per cent, load factor, I think the council would be well advised to consider completing the tunnel 9ft. 2in. inside.” THE RECOMMENDATION. Sixth question: “Failing any satisfactory solution re increasing the output of the present Waiwakaiho scheme, sufficient to

cater for the ironsand demand, what is your opinion of the Waitara River scheme (as pointed out to you on your last visit to this district) relative to supplying the power, etc., required for iron smelting?” Answer: “I investigated the Waitara on a previous occasion, but for the purpose of making it fit into a general scheme of power supply as outlined by Mr. Parry’s report in 1918. For this purpose it was not considered satisfactory, but I am not in a position, with the information available, to express an opinion as to its suitability in any scheme of local supply.” Summarising his general conclusions, Mr. Kissell says: “For the purpose of a local supply for New Plymouth and the surrounding districts a further survey and investigation of the Waiwakaiho and its adjacent streams is desirable, and the council should favorably consider increasing No. 2 tunnel to the larger size.”

Mr. S. G. Smith, M.P., has received from the Minister of Public Works a copy of the report, which he is forwarding to the New Plymouth Borough Council.