INDUSTRIAL LIGHTING.

Auckland Star, Volume L, Issue 155, 1 July 1919, Page 7

INDUSTRIAL LIGHTING.

THE AKAPUNI DAM SITE. BORING PROSPECTS GOOD. PROBABLE CHOICE FOR STATION. Our Cambridge correspondent informs us that the prospecting work at Ajapuni to discover whether the construction of. the big dam across the Arapuui Gorge would be practicable, is turning out very favourably, aud that there is ;iow every probability that the main hydro-electric station for the Auckland province will be erected at this site. In the course of his report on hydroelectric development, Mr. E. Parry, M.1.1-l-., in discussing the advantages of Arapuni over Aratiatia as tbe site for a main high power station, pointed out that it was 45 miles nearer the main market in Auckland, while it was not much farther from the other market in Taranaki. He goes on to say: "The transmission line south to Taranaki and the Main Trunk districts does not have to cro« the same amount of undeveloped country as from Aratiatia, but will everywhere traverse country that is in process of development along the railway routes. It is to be expected that the loads along the routes of these transmission lines will develop rapidly, as the heavy sections of railway tbereou I require electrification, and the settlement increases with improved condi- | lions. The scheme of development proI posed is to build a dam in the gorge of i the river, raising the water level about 140 feet, and diverting the river into an old parallel channel at a higher level. "Some 60 chains from the dam this old

channel approaches within eight chains of the existing channel, nnd at an elevation of 165 ft above it. Here a low weir will be built across the channel, and the water required for power will be taken through pipe tunnels to a power house on the present river bank. From observations made during the low water flows in 11)15 it is estimated that we could ultimately instal a plant capacity of 162,000-b.p. in this station. To fill its function in the universal scheme outlined in this report a plant capacity of 96,000-h.p. is required. At this stage the development becomes an exceptionally economical one, and the cost of supply on to the main transmission lines as in the other cases is estimated at fI.OTS.TOO or £10.7S per horse power. If the scheme were ultimately extended to its limit it is likely that the whole plant capacity- of 162,000-h.p. might be installed "for £1.4-20,707, or £S.7S per horse power. Partial developments of this source would be relatively more expensive owing to the cost of the large dam having to be incurred from the inception, but it is estimated that even a partial development of :V7.:i<lo-h.p. can be put in for £20 per horse power. I'nless exploration work proves special difficulties to exist at Arapum, it is unlikely that Aratiatia will prove a better source for generation." THE HORAHTVRA PLANT. The statement made by the Minister of Public Works (-ir William Fraser) to a representative of the "Star" last week, that he hoped the negotiations for the acquisition of the Horuhora plant by the Government would be very shortly completed, is causing much satisfaction in the Waikato, the people of Hamilton especially looking forward to getting water-generated cheap electric power in thjc near future. In dealing with the necessity of having an immediate market available for the power to be generated at Arapuni or Aratiatia, Mr. Parry remarks: "Either of these schemes, which have very large ultimate capacity, and which -will later become the main source of supply to the island, involves heavy expenditure in the earlier stages, and will take some time to construct. The acquisition of the

Waihi Company's plant at Horahora suggests a possibility of obviating this to some extent. At present this plant is only working to half its capacity, and, the Waihi Company's main interest being goldmining. no great efforts are made to develop the power business and so dispose of this surplus power. It is probable that if this plant were taken over by the Department, and lines built into Hamilton, the balance of power would soon be absorbed, and in the mining districts on the company's existing line. The license issued to the company gives the Government the right to take over the-e works at any time at valuation. I"p to the present the station has been working to only about halt*' its full-rated capacity, and further expenditure on headworks would be necessary in order to secure the fullrated output of the fi.OOO kilowatts now installed with the freedom of interruption which is essential in an ordinary cnmmercial undertaking. It is possible to augment the supply at Horahora by a development on the Pokaiwhenua River, giving 1 fi.OOO horse-power in all. but is not recommended. The amount of power to be so obtained would be. so small that, after supplying the needs of the balance of the mining districts near tho Waihi Company' 3 existing lines, and running lines to Hamilton. Cambridge, and local markets, thpre would only be a limited amount —■ about 7,000 horse-power —left, to supply Auckland. This amount is not nearly sufficient for the present requirements of Auckland, and would only emphasise the need of the larger development."