THE POWER SCHEME.

Taranaki Daily News, 22 August 1922, Page 5

THE POWER SCHEME.

PLANT FOR THE EXTENSIONS. VARIATION OF PROPOSA. -J With regard to the electrical pMLrequired at the New Plymouth hydroelectric extensions, the Borough Council last night had before it correspondence which has passed between the borough manager and the electrical engineer, which, in view of the early completion of the partial scheme, is of interest. The borough manager stated: The variation of the electrical engineer’s original proposals now recommended by him is certainly in the best interest of the undertaking. As pointed out by him, it entails an additional expenditure not previously contemplated of approximately £5200, and before anything definite can be decided it will be necessary to go closely into the question of i finance, more especially a compara-, tively large sum must necessarily be required for extension of mains, purchase of meters, etc., in connection with the disposal of the output of the plant when the works now under construction are completed. I will submit a report in regard to this phase of the question as soon as I am in possession of the necessary information.

The letter froun the borough mnnauer to the electrical engineer stated: On the 3rd of August of last year I wrote you intimating that I should like to feel more satisfied that sufficient electrical machinery had been ordered to deal with the electrical supply when the civil engineering portion of the work had been completed. You then reported very fully upon the matter, sobwing that one 1500 h.p. turbine and alternator was on order, and intimating that you intended altering the existing turbines when the water was available on the higher head. When this is done yoh wrote “the station output is brought up to the maximum river output of 3000 h.p., and in addition to this the machines will have an overload capacity of approximately 25 per cent, for two lines.'* In supplying the information in regard to the existing plant, which I required In connection with th/> visit of inspection by the Taranaki Chamber of Commerce, you stated in your memo that the 500 h.p. set would operate on the higher head, giving an output of approximately 750 h.p., but in regard to the two 250 h.p. sets: It is the intention that both of these machine® or sets will remain unaltered, and will be used in conjunction with the existing pipeline tunnel and dam to supply power over peak load and other limited periods. Thi®

may, perhaps, put a different complexion upon the matter, and I should be glad if you would kindly let me know what the total output of the station will be when the 1560 h.p. set is installed and the 500 h.p. set is altered and working on the higher head: (a) With the river flowing 150 cusecs, and (b) with the river flowing 100 cusecs.

The electrical engineer’s reply stated, inter alia: Your contention is perfectly correct. I have always calculated on the 3000 h.p. In connection with the above scheme, being obtained by: (1) New turbine, 1560 h.p.; (2) alteration turbine No. 2 (existing), 750 h.p.; (3) alteration to No. 4 set (existing), 350 h.p.; (4) alteration to No. 5 set (existing), 350 h.p.; total. 3010 h.p. We cannot alter any of the existing machines for the new head conditions until the 1560 h.p. turbine Is installed and running, but we can make all preparations to do this work with a minimum of delay as soon as this machine is running. This is what is being aimed at, and the complete gear for the alteration of the first machine will be to hand this week, and if the original idea is to be carried out the gear for the remaining two machines should be ordered very shortly. After a good many months’ consideration I am convinced that although my first recommendation is the cheapest, I can now put forward something which is better. It is in connection with leaving t)ie older low head sets unaltered and to duplicate the new 1560 h.p. turbine almost immediately. The effect of the altered recommendation would be that we could get approximately 450 h.p. for three hours per day (minimum), say, over peak load period if we retain these two low hesd machines. He adds: One is apt to neglect the fact that in the scheme E2 the Mangamahoe is running to waste, and its minimum flow is approximately 6 cusecs, or when stored (and the storage existing Is sufficient) it will, on the existifig head, produce 450 h.p. for approximately 3 hours. The coat of altering these two low head sets on the old tender, dated August 4, 1920, was .£1630 each, or £3-260 for the two. To-day’s price will probably be approximately £2BOO for the two. and their combined output would be 700 h.p. A duplicate of the 1560 h.p. set will probably cost £BOOO approximately, to-day, or a difference of £5200, But the arrangement will be a much better one, and enable us to make better use of the high head water, and also use to advantage Mangamahoe water, plus any excess from the high head, and I strongly recommend it, providing that it can be financed.

In reply to your questions (a) and (b): (a) The total output of the station under this heading will be 2310 h.p., requiring 105 cusecs. The balance. 45 cusecs, will be used in the low head machines, and also run into storage existing, and on the low head machines produce 450 h.p. direct. This will be supplemented by the storage and load factor, a safe figure 550 h.p., making a total of 2860 h.p. with 150 cusecs flowing, (b) With 100 cusecs flowing It will all be used by the high head machines, producing 2000 h.p., but 450 h.p. additional would still be available for three hours per day from the existing storage and low head machines with the Mangamahoe flGwir.g at 6 cusecs