THE DEVELOPMENT AND FUTURE OF ELECTRIC MILKING IN NEW ZEALAND.

New Zealand Journal of Agriculture, Volume XXVI, Issue 3, 20 March 1923, Page 156

THE DEVELOPMENT AND FUTURE OF ELECTRIC MILKING IN NEW ZEALAND.

LAURENCE BIRKS, B.Sc., M.lnst.C.E., &c., Chief Electrical Engineer, Public Works Department, in the New Zealand Journal of Science and Technology. Following an article by the author on electric power for milking, in Volume 4 of the Journal* it is of interest to note the present position of this development, which promised and still promises to grow to such large dimensions, though naturally -the drop in prices of agricultural products generally has delayed the extension. The returns show that there are already over a thousand milking plants operated electrically in the Dominion from public electric - supply systems in addition to those operated from private electrical installations, and the number is increasing rapidly. In Canterbury electric power is as yet generally available in only three farming districts, and the numbers of electrically operated milking plants in these districts —Tai Tapu district, 36 ; Eyre County, 4 ; Rangiora County, 32 ; the charge being £2l per year per 3 h.p. motor. The supply will be available this season in the Banks Peninsula, Ellesmere, and Kowai Electric-power Districts, and it is anticipated that the season will open with about fifty milking plants in each district. The charge in these districts will be £6 per horse-power per year, plus a unit charge of 3d. for the first 80 units per month, 2d. for the next 120 units per month, and i|d. for all over 200 units per month. In the Hawera Electric Supply Company’s area there are fifty milking plants operated electrically. The charge is by meter at the rate of 4jd. per unit, less 10 per cent., and the consumption and annual cost for four typical milking plants for last season were as follows :

These figures correspond fairly closely to those given in the previous article for the Canterbury examples —viz., 1,244, 922/675, and 1,919 units per year—and the distribution over the year is practically the same. They work out at o-gSd. to o-49d. per pound of butterfat. The reduction of demand for the midwinter months is, of course, particularly advantageous to the electric-supply authority in that it permits of the sale of the power elsewhere at the time when the demand for lighting and heating is the greatest, thus improving the load-factor. In the Stratford Borough area eight plants are operated electrically, the charge being 4d. per unit, with a maximum of £l5 per year. The Murchison County has just installed a 100 h.p. automatic generating plant, using an old gold-mining water-race, and has run nine miles of reticulation, to which four milking plants are already connected. ' >

In spite of the recent depression in butter-prices, the conversion of the milking plants in the Waikato district to electric drive is proceeding rapidly. The distribution in the farming districts of the power from the Government plant at Horahora Rapids is in the hands of four Electric-power Boards ; viz., Thames, Te Awamutu, Central, and Cambridge. Supply was commenced in Thames and Cambridge districts early in 1921, but in Te Awamutu and Central it was practically into the opening of the milking season before supply was generally available, and, as a result, the conversion of the majority of the milking plants was postponed until the coming season. In spite of this the proportion is very substantial, as set out in the following table :

The rates for energy in Thames Valley are £2l per year up to 7,000 lb. of butterfat produced, plus |d. per pound of butterfat in excess of 7,000 lb. This works out at about ’ |d. . per pound of butterfat for a herd of thirty-five cows producing 7,000 lb. of butterfat per year, and proportionately higher for a smaller herd and cheaper for a larger herd, down to o-48d. per pound for a herd of a hundred cows of good

average yield. In the Te Awamutu district the rate is £6 per year per horse-power of connected.load, (usually 2 h.p.), plus a unit rate by meter of 3d. for the first 80 units per month, 2d. for the next 120 units per month, and i|d. per unit for all over 200 units per month. In the Central and Cambridge districts the rates are practically the same. In the Te Awamutu district the following are a few representative costs at the above rates :

These include the highest and lowest charges in this district, the balance ranging between £2O and £3O. They range in cost per pound of butterfat from |d. in the large herds up to id. in the smallest herd. The competing. source of power for milking purposes is benzine at £1 is. to £1 ios. per case, according to the distance of cartage from the railway-station, the consumption usually ranging from twenty to fifty cases per year. The electric power thus has no difficulty in competing on the score of cost of fuel alone, apart from the lower cost of maintenance, lower first cost, and the great advantages of reliability, simplicity, and ease of operation of the electric motor as compared with the oil-engine. The number of electrically operated milking plants is much less than it would otherwise have been, owing to the drop in the price of butterfat rendering the financing difficult to many dairy-farmers. The Thames Valley Board had met this position from the start by financing the farmers and undertaking the work of installing the electrical system, and hence the .large proportion in its district. The Te Awamutu and the other Boards are now making arrangements to advance the cost of the installation on time payments, and,, as a result, the proportion of electrically operated milking plants in these districts will probably be as large next season as in the Thames Valley. As a further method of cheapening the cost of installation Jthe Boards are arranging, where practicable, to call comprehensive tenders for the whole of the wiring and installation of motors for groups of farms up to fifteen within a given district simultaneously. As a result of the arrangement, applications for electric supply are being received so fast in some districts that it is difficult to deal with them all. Moreover, owing to the saving in transport expenses on the part of the wiring contractors, the cost of the installation is materially reduced by this grouping of the work of installation.

In addition to those districts in which the supply is already available, the reticulation is being erected in several other districts, particularly in the Southland, Manawatu, Rangitikei, Horowhenua, Wairarapa, Opunake, and Kaponga districts, where the necessary plant is being installed, which will involve a large increase in the number of electric milking plants in operation within a couple of years.

The history of the development of electric-power milking has been the replacement of the standard 3 h.p. oil-engine driving the ordinary releaser milking-machines by, first, a 3 h.p. electric motor. This was. found to be largely in excess of the power actually required, and that even I h.p. 7 ill operate sufficient milking-machines at once to deal with a herd of a hundred ' 1 1 cows. But a large proportion of the herds . range from ten to twenty cows, and for a herd of this size a plant capable of milking two cows at a time is. all that is required. A machine is now available of a much more compact type, capable of fulfilling this service, and driven . by a motor of only | h.p. Moreover, it has the great advantage • that the motor vacuum - pump and releaser are all mounted direct on the lid of the

bucket, and the whole outfit is thus exceedingly portable, and can be carried about in one hand, thus reducing the cost of the building and accessory equipment required in connection with it -to a minimum. The complete apparatus is shown in the figure herewith. The cost of operation will also be much less than the standard i h.p. or 2 h.p. plants, though, of course, with the self-contained plant the separator and water-supply pump, if required, cannot be driven from the same shaft as is usual with the larger installations, and separate motors will have to be installed for this purpose. The Thames Valley Power Board have fixed a charge ranging from £7 per year upwards for the energy for this J h.p. outfit. Though it will probably not take the place of the standard arrangement for large herds of thirty to one hundred head, the |h.p. unit will probably have a large influence in extending the demand for electric power for milking the smaller herds of the Dominion. "

' Areas in Orchards, Gardens, Tree - plantations, &>c. ■-Particulars of the area in occupation in New Zealand under this class in 1921-22 (aggregated as i 46>346 acres on page 123 of February Journal} are as follows : Commercial —Bearing, 17,607 acres ; not bearing, 7,604 acres. Orchards for private use only, 5,910 acres. Vineyards, 179 acres. Market - gardens, 4,262 acres. Nurseries and seed - gardens, 395 acres. - Private gardens and grounds about residences, 57,927 acres. Plantations, 52,462 acres. ,

* Reprinted in the N.Z. Journal of Agriculture for August, 1921

[Note.This table is brought up to 6th March, 1923.]

Farm. Number of Cows. Total Units. Annual Cost. A . . 75 . I , 801 £ s. d. 30 8 3 B . . . . f. ' 50 1,001 17 6 10 C 34 706 12 16 0 D . . 28 502 . 816 0

Farm. Sept. Oct. 0 Nov. Nov. Dec. a Dec. aS rO Jan. O 1 Feb. cS Ph ' g Mar. < April. May. May. ■ June. June. Aug. July. Aug. A 159 252 148 212 242 188 192 250 132 26 B 90 144 100 115 120 104 115 141 . 72 C 63 73 108 69 123 90 96 84 D . . 51 81 51 69 8l 57 57 75

Monthly Demand (Units).

■ — Thames. - Te Awamutu. Central. Cambridge. Supply commenced. . . .' 11/3/2 1 26/8/21 I3/7/2I 28/4/21 Number of milking plants in whole district 2,000 850 600 200 Number within reach of the mains 900 700 330 250 Number already converted or being converted to electric drive 450 150 250 100

Number of Cows. Horse-power. Cost of Electricity for Year. • £ s. d. 18 .. ...: • .. I £ s. d. 15 18 6 29 . .. .. 2 19 1 9 90 .. .. ... 2 33 2 3 102 .. 2 2819 0