D.—l.

" Commercial" includes milking motors, other rural power, shops, street lighting, &c. Units used for departmental purposes are excluded. In addition to reducing the price of electrical energy to retail consumers in Southland the Department abolished meter rents as from Ist October, 1936, and as from Ist April, 1937, discontinued the former Southland Electric-power Board's practice of levying land rates. One of the features revealed by the annual returns is the growth of the unit consumption in respect of three of Southland's important industries —i.e., coal-mines, freezing-works, and lime-works. The following figures indicate that electricity continues in vital association with the industrial life of the district.

Notwithstanding reductions in the Southland tariff increases have been made in the total annual sales of electric energy (for all purposes in Southland), as shown in the following comparative statement £ 1935 .. .. .. .. .. 131,272 1938 .. .. .. .. ..147,136 1941 .. .. .. .. .. 157,727 The system designed to encourage consumers to pay electricity accounts in advance (a special allowance being granted to those who adopted this method) was continued. The object of the system is to enable consumers to eliminate the risk of losing discount through late payment of periodic accounts, to relievo consumers of the necessity of making frequent payments of small accounts, to reduce meter readings in certain cases, and to effect a saving for consumers in stationery and postages. During the year many consumers agreed to an extension of the Department's system of estimating electricity accounts, thus enabling the Department to curtail the use of petrol and otherwise to economize in transportation costs. These savings would not have been possible had the consumers demanded actual readings of the electric meters. The Department expresses its appreciation of this evidence of co-operation. Evidence of the popularity and convenience of payment of their electricity accounts at any moneyorder post-office in the district (other than Gore and Invercargill, where the Department's own offices are situated) is found in the fact that during the year 25,147 payments were made by consumers at the various post-offices. Bad debts written off during the year amounted to only 0-IL7 per cent, of the year's total sales of electrical energy. 2. Operation and Maintenance. (a) Power-stations. Monowai Power-station came into operation again on Ist April, 1940, after having been shut down for some months, during which time extensive overhaul was carried out. Final inspection and adjustments to the turbine governors were made by the contractor's representative. All load was dropped from Monowai on sth December, 1940, in order to restore the level of Lake Monowai, which has since risen to capacity. Accordingly full load has been carried on occasions to prevent further rise and overflow. New cables have been installed between the power-house and outdoor substation, and all apparatus in the high-tension yard has been appropriately coupled up to a new earth bus. The Invercargill City Council's steam-plant was brought into commission on several occasions during the year as required. (6) Substations. At Invercargill Substation work is proceeding with the installation of new 11 kV. switchgear and metering-equipment. A bank of three single-phase 66/11 kV. transformers with a total capacity of 4,500 kVA. is also in the course of installation. This bank will supplement the existing bank, giving a total capacity of 9,000 kVA. for the substation. At Gore Substation operation has been normal, while routine inspection and testing of apparatus has been carried out when convenient. On 29th December, 1940, an interruption to supply lasting forty-three minutes occurred due to the breakdown of an intersystem metering-current transformer. Instruction in live-line testing has been given at Gore, and subsequently all major lines and substations in the various districts have been tested. Faulty insulator units located in this manner have been replaced. In the Gore Borough a new 11/3-3 kV. outdoor substation consisting of a 300 kVA. bank of transformers has been installed to replace the old installation. Temporary rearrangement of the Winton Substation apparatus has been completed. This is to facilitate the installation of further steelwork and switchgear at a later date.

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For Year ended 31st March. Coal-mines. Freezing-works. Lime-works. Units used. Units used. Units used. 1933 .. .. .. .. 208,440 2,681,333 217,089 1937 .. .. .. .. 687,173 3,213,052 468,160 1941 .. .. .. .. 1,027,924 4,180,208 1,152,219