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War Economy

Electricity Shortages Worsen

Electricity Shortages Worsen

Completion of a new generating unit at Arapuni at the end of 1946 was a signal for attempts to reduce some of the more drastic power restrictions which had been imposed in the North Island during the war.

In April 1947 the first of the three units at Karapiro went into operation and more of the restrictions were removed or relaxed. But the shortages were far from overcome, and later in the year power restrictions had to be reimposed in the North Island.

In 1947 the South Island had its first experience of electric power rationing.

Hydro-electric construction was still hampered by shortages of imported components. Other countries had to overtake war backlogs, and some had to replace installations destroyed in the war. Countries supplying electrical equipment were unable to cope with the demand. Delivery of plant and materials tended to become worse for a time, and in New Zealand new stations could not be brought in fast enough to cope with the ever-increasing demand for power.

In only five years, between 1944–45 and 1949–50, demand for power increased by over a third.

In fact, the situation was to become much worse for some years, and one authority wrote:2 ‘In the early years of the last decade 1950 to 1955 an all time record was established in the frequency and severity of power shortages in both Islands.’ In considering generalisations of this sort, it must be remembered that, when supplies are tending to lag behind demand, the severity of shortages in particular years depends on the variations in rainfall in the catchment areas. Actually there was a more severe shortage in the South Island early in 1956, with a 40 per cent cut in rationing for several weeks, and in 1958 in the North Island, where a 15 per cent cut applied for almost ten months.

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Maraetai, the most powerful of the North Island stations, came into operation in 1952 and by 1954 was generating 180,000 kW.1 The North Island was free of controls from the middle of 1953 until the middle of 1955.

Hydro-electric generating potential had been developed faster in the North Island, to meet the faster increase in demand there. While there was still a large unused potential in the South Island, it was becoming progressively more difficult to find suitable new hydro-electric power sources in the North Island. By the middle 1950s it was generally recognised that development of all possible North Island hydro-electric sources would not satisfy the growing demand for much more than another decade. In 1956 the Government decided to investigate the practicability of a 25-mile submarine cable to link the North and South Island systems.

Meantime, other types of power generator were being developed. The geothermal steam station at Wairakei started generating with its first turbine in 1958. In the same year, the Meremere coal-burning station, its costs kept low by the supply of coal on an aerial cableway from open-cast mines, started feeding in power.

The last of the electric power restrictions were lifted at the end of 1958. Arrears had been overtaken and a demand for power 2£ ½ times what it had been at the end of the war was being satisfied. Demand was still increasing 8 per cent a year.2

By 1964 the inter-island cable had become part of the established programme. Construction of the shore links was well under way and the cable was expected to be in use at part capacity in 1965.3 Moreover, this was now thought to be necessary if there were not to be further power shortages in the North Island.

2 G. H. Battersby, Some Aspects of Electrical Supply in New Zealand, Canterbury Chamber of Commerce Bulletin No. 456, December 1962.

1 Half its ultimate capacity.

2 See also Chart 72, p. 426.

3 Benmore, in the South Island, was expected to be in operation in 1965 and would, until the completion of Manapouri, be the largest New Zealand station.