79

D.—l

The second consideration- viz., resulting economies—will be determined in each case by the operaing costs, and the prices at which the current can consequently be sold. These are estimated in detail later on for each Bystem, but taking as a preliminary basis figure the cost at which power was generated last year at the Waipori power-house of the. Dunedin Corporation—viz., £9 per horse-power year, or £12 per kilowatt year, including working-costs and interest charges—this is equivalent to the following costs per unit : — ',(!. for continuous working for 8,760 hours per annum. Load-factor, 100 per cent. .Id. for an average full load demand for 16 hours per day, or 5,850 hours per annum. LoadEactor, <>(i per enri. jd. for an average full-load demand for 12 hours per day, or 4,380 hours per annum. Loadfactor - r >O per cent. lid. for an average full-load demand for 18 hours per week, or 2,496 hours per annum. Loadfactor 28-5 per cent. 2d. for an average full-load demand for 4 hours per day, or 1,460 hours per annum. Loadfactor 16-7 per cent. To compare these with the actual cost of generation by steam plants in the other cities, taking the works costs only, and not including any interest or standing charges, these costs per unit are as follows :— Tramways. Eleo *™ Jji "'" and Power, d. d. Auckland .. .. .. .. .. .. 1-00 (approx.) 2-00 Wellington .. .. .. .. .. 0-79 3-08 Chrifltchurch .. .. .. .. .. 0-81 2-60 Of these figures the WOrMng-COSte shown in the second column of the municipal electric lighi and powerstations in Auckland and Wellington will both show considerable reductions (probably to one-half of the above values) when the new plant now in hand is installed. Again, taking the total costs, including capital charges, in each of these existing steam plants, the figures are as follows : Tramway*. Eleo *™ '' ; - ht ami rower, d. cl. Auckland .. .. .. .. .. .. 1-50 (approx.) 3-30 Wellington .. .. .. .. .. 1-26 5-06 Christchurch .. .. .. .. .. 1-23 MX) These figures show clearly that there is ample room to supply the tramway and the elect ric light and power plants in each of the three cities. Auckland. Wellington, and Christchurch. with electric energy in bulk from water-power at rates remunerative to both parties. In taking the Dunedin figures from their last animal report as a basis, it must be remembered that the Waipori water-power plant then had a capacity of only 2,000 kilowatts or 2.660-horse power, and the capital outlay includes the whole of the distributing reticulation. The power has since been increased to 4.000 kilowatts or 5,330-horse power, and consequently the above actual cost, £9 per horse-power-year, will be considerably improved upon with the larger plant and the corresponding smaller capitalization per horse-power. In the still larger power plants under consideration this reduction in cost will be much greater. But the above basis costs constitute a conservative rate on which to estimate the load in sight. Taking these figures as the basis, it is thus possible to effect a considerable saving to the ratepayers and the customers of each of these municipal plants by supplying them with power in bulk, both for tramways and for general lighting and powerdist ribution purposes, enabling their present steam plants to be held in reserve for meeting special demands. The tramway power-stations have been particularly selected for comparison, as they have been installed with the very highest type of power plant that modern engineering can produce, and are therefore working at the highest economy that is attainable. The smaller private plants of various descriptions are working under much less favourable conditions, and are costing from £15 to £30, and even much higher amounts per horse-power per annum. They would therefore find very much greater economies resulting from a bulk supply of electric power at the above rates than would the tramway stations. I have found in actual experience of electric-power supply that, in Christchurch at 3d. per unit, it proved economical for the majority of small factories to replace their existing engines by electric motors, and when new plants were required it was much cheaper. When the power-rate was reduced to 2jd. per unit net, it was sought after by the power-users taking up to 15- to 20-horse power. Had it been reduced to 2d. it would have replaced all other power plants within the area of distribution. In Dunedin the average cost of production and distribution, including interest charges, is only 0-BM. per unit, so that we may have every confidence in providing for the majority of the power-users within ihe area supplied as soon as the rates can be reduced to those adopted in the above basis of comparison. The third feature in determining the proportion of electric power that will be adopted —viz.. the cost to the consumer of the electric-motor installation —does not come into consideration when new industries are being established. In such cases the power plant has to be provided, and electric motors can lie installed complete for from £3 to £8 per horse-power, as compared with £10 to £20 per horsepower for steam-engines and £7 to £15 for gas or oil engines. In replacing existing plants, if the old plant is saleable, it frequently brings more, second-hand, than the electric motors cost it is not saleable, the change involves a slight additional capital burden. In special cases steps shoulc? be taken to assist the consumer in this, as is done by the gas companies and the Wellington Corporation Electrical Department, either by letting the motors out on hire or supplying and installing them on time payments to encourage the immediate loading of the plant and the consequent improved fin ancial returns. From the above data the following are estimates of the electric-power requirements of the four main cities in five years' time.

13—D. 1.