PART II.—THE SUPPLY OF ELECTRICITY

NZ Services Current Affairs Bulletin, Volume 2, Issue 10, 15 May 1944, Page 6

PART II.—THE SUPPLY OF ELECTRICITY

1. The Government is the Producer In New Zealand the Government has a monopoly of the actual venerating of electric power. The main reason for this is that the greatest potential source of electricity is water-power. Harnessing and converting this energy requires considerable capital outlay, which can most successfully be undertaken by the State. As early as 1896 the value of New Zealand’s water-power was recognized, and legislation authorizing investigation was passed. In 1903 the first Water-power Act came into force vesting in the Crown all rights to use water in rivers and streams for power purposes, with provision that such rights might be delegated in suitable cases. The first large-scale State hydro-electric project was undertaken in 1910 when the work of harnessing the waters of Lake Coleridge was begun. As a result Christchurch received a regular supply of power early in 1915. The development has been gradually extended, until it reached its final capacity of 34,500 kW. in 1933. Two other substantial hydro stations were actually in operation before that at Lake Coleridge—the Waipori development now of 17 OOOkW. capacity, on the Waipori River, 30 miles from Dunedin, and the Horahora station, now of 10,300 kW., on the Waikato River. Both these were begun by private companies, but early in their develop-

went they were taken over by the Dunedin City Council and the Public Works Department respectively. Waipori went into commercial operation in 1907 and Horahora in 1913. 2. Hydro-electric Stations Practically all our supply of electricity is generated in hydroelectric stations. There are forty main stations in New Zealand, ' -of which 32 are operated by water-power. The remaining 8, all in the South Island, are made up of seven oil- and one steam-plants. In 1942 the total installed capacity of all the main stations was 340,755 kW., of which 338,798 kW. was hydro. After Lake Coleridge the next large hydro project was undertaken •on the Mangahao River in the Wellington Province. Operating on a head of 896 ft., this station went into commission in 1924 and has now a capacity of 19,200 kW. This was followed by the State scheme at Lake Waikaremoana, which utilizes the overflow and seepage waters from the lake. In 1929 this station added 32,000 kW. to the system. Further development has recently taken place at Waikaremoana. The original station is now known as Waikaremoana Middle. Using the same water at a lower level, Waikaremoana Lower station was recently completed with one generator already producing 20,000 kW. A second of equal capacity is expected to be operating shortly. A third station, Waikaremoana Upper, has been begun. It will use the water before it comes to the Middle and Lower Stations. Work is progressing on the tunnel and headworks, and the machinery is on order. This will add 32,000 kW. to the supply. So far the largest hydro-electric development in New Zealand has been at the Arapuni Gorge, on the Waikato River, six miles up-stream from Horahora. Here six turbines drive generators with a total capacity of 110,000 kW. It is planned to install two more units which will bring the station’s total output to 150,000 kW. One of these units should be running this year. Both were ordered in 1939, but delivery of the second is at present uncertain. In order to ensure a maximum all-the-year-round flow of water to the turbines at Arupuni and Horahora the channel of the river where it leaves Lake Taupo has been deepened and control gates installed. This work is estimated to have resulted in 9-35 per cent, more units being generated at these two stations during 1943. , & In the South Island there is an abundance of water-power as yet comparatively untouched. One estimate places its potential horsepower at six times that available in the North Island. The largest hydro development so far undertaken in the South is on the Waitaki River, where a huge dam has converted a river valley into a lake giving an effective head of 70 ft. The present capacity is 60,000 k W., and additions are proposed which will give a total capacity of 75,000 kW. . 1 ;

At Highbank, near Methven, work is almost complete on a new station which will have one 25,000 kW. unit in operation this year. This is a co-ordinated irrigation and hydro-electric scheme using the waters of the Rangitata River. A hydro-electric station is also being’ constructed in the Cobb River Valley to supply the Nelson and Marlborough districts. The remaining main stations are, generally speaking, smaller plants that have provided power for local requirements over a long period. Some are operated by private companies under license from the Government. In general, all these stations are now linked with the State inter-connected power systems. Work on building and installing machinery in hydro-electric developments has been pushed ahead during the war years. It has, however, suffered as a result of the war. Both man-power and materials are in short supply. Just before the outbreak of war plant

sufficient to generate 236,400 kW. had been ordered. War hasdelayed deliveries, in some cases by over four years, so that the Government’s programme of extending existing stations and building, new ones has not been fulfilled. • 3. Standby Plant • The main stations of the North and South Island systems operatecontinuously in parallel. They are supplemented by 47 small standbystations throughout the country. These are called upon to augment the main supply during- “peak load hours and in emergencies. War conditions have necessitated greatly increased use of this plant. With an installed capacity of. 101,089 kW. these plants comprise 24 oil, 10 water, 10 steam and 3 gas. The steam-plants generate 78,102 kW. and the oil 18,719 kW. The largest standby plants are the steam-electric sets at the King’s Wharf station of the Auckland Power Board (41,460 kW.), theEvans Bay steam and oil plants, of the Wellington City Corporation (24,000 kW.), and the Penrose and Dobson Diesel-electric plants of the Public Works Department. During 1943 the King’s Wharf station burned 42,345 tons of coal, and the Evans Bay station used 21,262 tons of coal and 7,794 tons of oil. A feature of modern steam-power plant is its economy and efficiency. Whereas in 1880 it took 10 lb. of coal to produce one unit of electricity, the best steam-electric sets now generate a unit of power on less than 1 lb. of coal. . • ■ • 4. Distribution and Sale of Electricity Distribution and sale of electricity to the consumers is usually the function of specially constituted local bodies—Electric PowerBoards. Their members are elected on a residential franchise. There are 45 of these boards at present serving 255,715 consumers. Their areas of supply, much of which are rural, cover a total population of 981,310. In 1942, 1,546,264,846 units of electricity were sold toconsumers throughout New Zealand. The Power Boards sold--923,914,080 units, at an average charge of 0.885 d. per unit. . . -. In a number of urban districts (44) the retail supply is handled by the City or Borough Councils. In 1942 the number of consumers under these “other Local Authorities was 184,265. They sold 500,749,456 units, at an average cost of 0.896 d. per unit. f ? Electrical development in New Zealand may be measured fairly accurately by the proportion of the population who may enjoy the service and by the average use each person makes of it. The population included in the various electric-supply areas is 1,634,338—ju5t over 97 per cent, of the total population. In 1942 the number of units sold per head of the Dominion’s population was 887. The average number of units sold to each consumer was 3,089. . These figures do not include the power sold for large industrial and tractionpurposes.

These figures place New Zealand about sixth in the scale •of electrified countries, after Norway, Canada, Switzerland, Sweden, ; and the U.S.A. They are misleading, however, as a guide to domestic •development. Most of these other countries owe their greater use ■of electricity to large-scale manufacturing and railway electrification, not paralleled here. It is probably true to say that nowhere else in the world is purely rural reticulation so fully developed as in New Zealand. Alongside increasing supply and consumption, retail charges for •electricity have been continuously decreasing. Within the past ten years the average cost per unit to the consumer has been almost halved. Cause and effect here are interdependent. Increased use •of electricity has made possible reduced charges, while reduced •charges have resulted in greater use. In 1942 the average charge to the consumer for each unit sold was 0.858 d., which is low by comparison with other countries.