HYDRO-ELECTRIC POWER.

Manawatu Standard, Volume XLII, Issue 10106, 13 October 1917, Page 3

HYDRO-ELECTRIC POWER.

< SCHEME FOR NORTH ISLAND. \ REPORT FROM PUBLIC'WORKS UErartment engineer, I A report on the hydro-electric dcvclopinout scheme for the North Island is contained in the Public Works Statement, presented to the House of Kepi'oSoUtativeS On Thursday. M,r F, i’atTV (eloetriral engineer) in tins rcpeW Mate's the present position of the investigation into the scheme of developing thq.y.-ater-powcr resource's ..f (he North , Before relating tint 'actual position ■of Ifto . work of investistilion he records jso.no underlying. principle; which governed I it is. «e(km* in preparing the rcheino, “ft. in, 1 think, clear,” states Mr Parry, “that ii supply from a;sJiig|o noUfCe Sr, hot, tiie host rolution of the jirohlent of a general supply for the North Island; and the question arises :!« to what is the next largest possible concentration which can he.effected, (laving regard to all oireiunstaneos. It is quite obvious that the unit be its largo a.s possible, HU I .Htllj* oil general principles, but also o!t the special ground that small water-power developments are unduly costly. Generally speaking, a. water-power tourco of loss.than about 30,000 luuseqiowcr cannot lie economically dev,*loped, . . . The scheme which be*'! satisfies all -requirements i:- one in which, at the outset, three, water-power sources .would he developed lor supplying respectively the .Auckland district. the Hawke’s Bay district, and the Wellington district. These' sources would, in the. ordinary course of development, be fluked up together, and by reinforcing cadi other provide additional guarantee ot continuity of supply. Regarding the source of power for Hawke’s Bay district, undoubtedly the best is Waikaremoaim. The amount of power obtainable trom this source is greatly in excess of the requirements of this district, and it should he regarded as a supplementary sourro for supplying the Wellington district. Very complete surveys have been carried out during last, year, and accurate measurements made of tho flow, and all the necessary information obtained to enable the most economical method of development to 1)0 prepared and carried out. SOURCE FOR THE WELLINGTON DISTRICT. “As regards a source of supply for the Wellington district, considerable difficulty has been encountered in finding a source which satisfies all requirements, because, all hough tho rivers are numerous, they do not lend themselves!to economical development, and, as a rule,’ the power to be derived from any one course is small compared with the requirements. It has been suggested that tho Hut river would form suitablesource for supplying the southern end of the Wellington district. The amount of water is barely adequate for live needs of Wellington city, it provision i.-: to be made for natural growth and progress, whilst for tho amount of power available the,.cost of development is excessive. Ju any case, tho amount of power obtainable is not large enough to Supply an extended district, whilst a power .station in tho Mnnawatu - district is'well situated for supplying Wellington, Wairarapu, and parts _of the Hawke’.;. Bay and Taranaki di triet,-, having regard to the distances and the power to bo supplied in each locality.

“Attov cdiiM'li-raWo investigation, the most ajiißible' source for the fjappjy of the southern- district is found to be the Mangahao river. This river rhes on tie-,slopes of Mount Duudas, on tho. Tararna ranges, and flows into tin; Manawatu near, Woodville, and it is found, that by _ diverting through the hills for a- total distance of three miles there, is made available the fall of 10-10 feet, in the sixty-live miles of river between the Mangahao and the loon of the Mftna.wa.in near Shannon.. It is proposed to develop lids source by tunnelling through the range from the Mangahao into the 3 okomam valley, there diverting a. payL-of the Tokoma.ru,* and then throuffit from the Tokomam valley through into {die valley of the MangaPre, with ti power station situated within three, miles, of the railway at Shannon. “Observations of the How were made during last rear-on, which was exceptionally dry, arid am also being made during the present dry season, anil, based upon the dry season How, it is possible to obtain 25.000 horse power on a. 50 per cent loadfactor basis by impounding'the -waters and taking advantage of the natural features of tiro country for. the .purport', 'this is sufficient to satisfy the power requirements of tho district which it is. intended to serve for some time to come, bill- will require to be supplemented in due course as the country develops! The natural extension of the transmission lines trout three sources will ultimately link thom_ together, k» that by this means security will hfp obtained, and additional supply obtained for the Wellington district from the ( other .sources. II is possible, however, that hi eour-c of time the requirements will he so great as to require another development m the Taranaki district,, where there is more than one promising .senree. “In the" design of this scheme I propose to adopt a new principle in regard to the provision for a-stand-by. It i- nccossary to provide an additional power unit over and above the [lower obtainable from the souice, so'.as to permit'of the overhaul and repair of machinery. The usual medi.-M is to instal an extra unit oi water-plant in me power-house. In the present instance I propose that the standby unit should be a complete steam set. r l hj“ advantage of a steam standby set in this scheme is that not only <joes it'serve the purpose of a spare unit, but it also provides means c»F tiding over short periods cl exceptional or abnormal low water, thus enabling the available water to bo used to a larger extent, the additional cost of a ; steam unit over a water-power unit is not, great, -and the■ cost of running on infrequent; ocdtiKionk would be ii negligible proportion of the .'total operating co-st, whilst the acldiUoiiai eeoinity and value conferred on the water-power plant is out.' of all ■ proportion to the added expense. A SUITABLE-STi:AM PLANT.^ “I would propose, further, instead;*>t installing the ~tcam unit at the,. powerdiou.se, to take a.dvantage, ot the'fact, that- Wellinglon City has already. a'- ?rt-oani plant installed, which is of tho capacity' required for the j>urjX,>so aforesaid, tuid. as inov ''pi Jeein it- advisable and prudent■ to 1 maintain this in running; condition to provide againM. temporary of tho supply, whiok axo incviiaWo on cycrvsvivtcjn, 1 liorp, should bo no ui lucidly about coining to terms fur the use of this plant for relieving tho load on the water-power plant in case c.-t necessity. Smite modification of the existing Wellington plant- may be. necessary -to lit in with this scheme, but this is it detail about which there should be no difficulty in the matter, which iti to the advantage of both parties. “ Tiie cost of providing headwork.s, powerstation, uud plant fop 25,000 horse-power would he, at normal prices, -120,000, which is ■under the limit of £2O per horse-power specified 'above, dins illustrates the advantage of concentrating: the power supply for a. considerable distance in one source. If, for instance, we .sought to provide.’.full the heeds of Wellington City and immediate neighbourhood only. from this source, the Cost of hydraulic works for the power required would bo excessive, whereas when tie. veloped for iho full capacity and for the benefit of a larger area and; population, it becomes a sound commercial proposition. “As regards the area to be supplied, there is an economic limit to the- area over which a given amount of power can be distributed, and one of the obstacles to a. salts-, factory scheme. of mover supply in New Zealand at. present- is tho small amount of power required per fopturo mile of a-rba supplied. Having regard to this-principle, and Mi-etching■ it to the limit; we should be woflcing'. on! economical lilies in serving the follow ing districts from this source; tho whole of tho Wellington province as..far north as: Ttxihapo and Wanganui, and the southern portion of Hawke’s Hay. I would propose, lit tho- first place, to run trunk lines to Wellington and Palmerston, North, .Wanganui, and Masteri-on as,chief centres, and from these centres, as well as frotu intermediate points oh the trunk lino, to •provide the necessary distribution lines and rub-station,,- to serve the .surrounding districts. THE COLT. “The cost of providing the trunk lines, distribution lines, Hilv.-thtious, and other services' to give a supply in bulk to local distributing authorities, and to largepoweruaera throughout this area' would be £530.000, making a total of '£1,000,000, which expenditure- is at the rate of £4O per horse-power. The capital - charge* oh this e:\pehditttre, at 74 per cent, to include interest. depv-cciaHwi,. and sinking fund, work out at £5 per horse-power per annum ; tho annual cost of maintenance and operation would amount to £25,W0 i«-r an urn, or the equivalent of PI per hbr.gt-'powof per annum- Both charges rsqiiito.a rSiara of i:4 on ti;3 average, par hotoj-pcv.'cr p£i annum ip; order ro provide'for all charges

with a reasonable provision for depreciation. | Wo know by experience in (’hristcluirch , that wo can secure .this revenue-without difliculty, cvcfi where economical fuel plants are already installed. •‘Tim development of the Mangahao would help Wellington out of a difliculty, and f fViti the Goviirimicnt’s point of view AW!-, limßon alone would provide an immediate ) loiul on the station of about one-third of its capacity, and would enable (he largo area- outlined above to by supplied at, tin* S nmc time both economically it nil acßanand the prospective markets in i these districts, combined with tho- natural increase in Wellington, tfhou'd absorb the. balance of the power available in a very short lime, , , , , ‘‘Complete nur-'eya have been made at (no Mangahao scheme, and plans and estimate' prepared. A survey of the transmission line, between Shannon and Wellington is iiroceedimr and will shortly bo completed, and (he poxilion of the sub-station to serve Wellington alid the Hutt valley has been MADE. “Summarising tho foregoing, the scheme of development recommended is that three 'voUrces of WatC-pdwer should be developed in the first place- Lai;* Waikartv moana,. for tho Hawke’s Bay district ; Anipiirii Gorge, or some other to be selected, for tho Auckland district; and the A lan? ahim river for the Wellington district. these three sources, in a. natural course, of extension will get linked up together, thereby enhancing the value of each source by adding to the security of supply, ami eft*. aiding'a continuous output to be maintained throughout, tho. whole of the Island. “The position in regard to the investigation now is that detailed surveys have been made of tho .Mangahao river, of Aratiatiarapids on the Waikato, of the Arapuni gorge, and the We.ikato, Bokaiwhcnua, ami Wai'pa rivers near Hoi-ah.ua, and of Lake WtiikaromoaJia. Further investigations and calculations utilising existing .survey information have been made of_ tho Hutt river, Huka Fall-. Kahuna nver, and otiier scheme.;. Observations of How, made during the recent sequence _ of dry season; have necessitate*.l a modification ol previous estimates of the power obtainable from the various sources. A survey staff is at present engaged on the transmissionline between Shannon and \\ ellington, amt will shortly be transferred to the Auckland district in order to survey a route for tho trunk' line between tho Waikato and Audill“Uonriderab!e difliculty ha; been found in maintaining the stall for survey puiposes, and we have at present only one survey party at work, whereas there .should be three, or four, with corresponding office staff in order to carry out the work expeditiously; but under present conditions it is found impossible to keep the- parties together,for long, and we have to be content with slower progress. “As regards the order of dcviAlopment, tho Waikarcmoaria. scheriie should be* neie!red for the present. The developmePt <>. this sourco should, to my mind, be maclo pendent upon the construction of •--*>- Napior-Gisborne railway. '1 he railway should open up a- better toad for the train.mission lines, ami render them more ac-ca sihle for the construction and mamtenar. -c. At present this country is most oithcuU, ospeciallv from a maintenance point of view. There is every 'reason, also, in favour oi operating tin- railway electrically. “The Auckland and Wellington s cnemc3 should proceed simultaneously. 'llm workin count.'(inn with the latter, however is more advanced, and, if labour is obtainable, which is very doubtful, the headworks could bo put in hand at once and prepare; in readiness for machinery and pipe-lines, vriiich, however, could not be obtained miring the continuance of the war. A beginning could be made, perhaps, by constructing road wavs for access, to the headwork.-. “Tho schemes outlined alsjve provide for the need of the more settled portions of the count rv. and imnmurate a. general weenie of distribution which will, in^ course-of tunc embrace the whole country. J