MAJOR WORKS

Ashburton Guardian, Volume 60, Issue 82, 17 January 1940, Page 2

MAJOR WORKS

HYDRO-ELECTRIC SUPPLY. HIGHBANK AND TEKAPO PLANTS. (Special to the “ Guardian.”) CHRISTCHURCH, This Day. The increase to 60,000 kilowatts of the capacity of the Waitaki hydi'o-elec-tric power station, the development of the Rangitata-Rakaia scheme at Highbank to make it available by the winter of 1941 and the pushing ahead of the Tekapo scheme to produce power by 1943—that, in short, is the Government’s immediate plan for power supply for the South Island. • “It is somewhat far-off to say definitely wlrnt will happen after these works are completed, but it is probable that the fifth and last unit of 15,000 kilowatts will be ‘ installed at Waitaki, and additional water stored in Lake Oliau and,' possibly, in Lake Pukaki,” said the Minister for Public Works (the Hon. R. Semple) in an interview yesterday in which lie made special reference to the significance of the Highbank and Tekapo development works. The development at Tekapo to provide additional storage for Waitaki and a' new station near the present township entails the piercing of a tunnel more than a mile long between the lake and the Tekapo river.” When that is done, it will be possible to generate power,” said the Minister, “and by so doing, to reduce the level of the lake until the bed of the stream flowing from the lake is virtually exposed. A regulating dam will then bo built at a site to be chosen. At present it is not quite clear what typo of dam will be used for this purpose, but boring tests to determine the depth and quality of the foundation materials are now in hand. It is hoped soon to be in a position to design the clam and to define its position.” Units for Waitaki. Of the main stations in the South Island, Waitaki is, as yet, only partially developed. Both the Lake Coleridge and Waitaki stations obtain most of their water from the higlr country and, consequently, the low-water seasonal flow is iii the winter when the demand for power is greatest. Of necessity, provision for storing water for the winter season has to be made. Lake Coleridge itself has been indispensable on that account. .

The full development of Waitaki to produce 75,000 kilowatts entails storing water in at least two of the three lakes—Tekapo, Ohau and Pukaki—in the Mackenzie Plains. As planned, a . third unit of 15,000 kilowatts was to be added to Waitaki’s first equipment of 30,000 kilowatts and it was then proposed to build a storage dam at Tekapo and, at the same time, to make provision for a 20,000 kilowatt power station at that point. The demand for power has grown so sharply that two additional units are now being installed. A Summer Supply. The expectation that a moderate supply of power may also be developed at Highbank during the summer months, especially in the earlier years before irigation reaches its fullest development, is held by the Government. The prosecution of the huge irrigationproject using water from the Rangitata river to irrigate the country between that river and the Rakaia made* possible the development of a substantial block of power by continuing the irrigation race to the hanks of the Rakaia and dropping the water clown into the Rakaia. A development of 25,000 kilowatts continuously during the winter, or peak demand season, is planned. “Such a block of power being readily available, the development of Lake Tekapo could be delayed for several years,” remarked the Minister, who, however, went on to explain the Government’s development policy, with emphasis on the course of the plans at Tekapo. It is 25 years since Government power supply activity began in the South Island with the opening of the Lake Coleridge station, the resources of which were gradually increased to 34,500 kilowatts. In 1934, Waitaki began operations 'with a'30,000 kilowatts ' plant. In 1936, the'Monowai statibn of 6000 kilowatts was resumed from the Southland Power Board. A standby Diesel plant (of motors from a wartime German submarine) was established at Lyttelton and later moved to Dobson, on the West Coast. Gjowth of Load. “The growth of load has been very rapid during the last five years,” c,aicl the Minister, who gave tlm latest compiled as follows:

The very rapid growth in 1937-38 and 1938-39 was duo to the. addition of the Monowni and Arnold River stations to the system.

Demand. • Generated, Kilowatts. Millions. Max. Units. 1,934-35 ... 32,500 149 1933-86 ... 36,700 171 1936-37 ... 44,500 205 1937-38 ... .58,200 274 1938-39 ... 69,600 326 1939-40 ... 76,100 ■Incomplete