Mr. Currie then proceeded to examine the three power producers from the factors affecting the choice of new pumping sets, nanu Comparative power cost of the unit which was tempered by the average overall efficiency of converting tne actual fuel to water horse-power; parative capital investment of the parative running charges; com. ting [Pnt Jand and contingent works applicable in interest and depreciation charges in the running cost of the plant; the supervision and labour available for erection and running of the plant; continuity of fuel and power supply; load factor under which the new plant would operate and the effect of such factor on the station as a whole; and, finally, variations in the flexibility of the various types of power and the resulting effect of such variations on the average overall efficiency.
Discussing the present policy, Mr. Currie said there was justification for continuing the purchase and running of steam turbine sets, electric pumping sets and diesel pumping sets on the main stations, and electric and diesel on the primary and secondary stations where the size of the units and their distance from the main stations did not permit the economic generation or transmission of steam.
Diesel plant, with its low stand-by charges and comparatively low capital charges, was suitable for peak loads and formed a suitable standby for electric plant. Electric pumps were ihe most economical but the source of power was not within the station. Steam plant, with its heavy standby charges and heavy capital cost, was suitable for high load factors only.
it would be seen, therefore, he concluded. that with an average station load factor of about 40 per cent, alternative types of power were economical as well as politic on account of local conditions.
Text read from the printed page and cleaned; old type leaves the occasional error.