New Sources of Power
New Sources of Power
WARTIME shortages of fuel and power were by no means restricted to the transport industry. Production, especially in manufacturing industries, was for a time hampered in meeting the demands of war by inadequate supplies of coal and electric power.
The war was but part of an era when manufacturing was increasing in importance relatively in the New Zealand economy and when motive power for manufacturing industries was tending to move over more and more to electricity. Steam engines, as sources of motive power in factories, decreased from 51,000 horsepower in 1937–38 to 37,000 horsepower in 1947–48. They provided 20 per cent of all factory horsepower in 1937–38 but less than 9 per cent a decade later. Though probably accelerated by wartime shortages of coal, the decline in the importance of steam power was already well under way when the war started.
In factories, oil was also starting to take the place of coal as a fuel for engines; 5 per cent of factory horsepower came from oil engines in 1937–38 and 11 per cent in 1947–48.
Thé waning importance of the steam engine as a source of motive power in factories did not cause a proportionate fall in the demand for coal. Many industries required large quantities of heat. Here coal could usually retain its place against electricity, though it tended to find a more serious rival in oil.
In the decade up to 1947–48 electric motors, which by 1937–38 were providing 72 per cent of the power available in factories, moved up to 80 per cent. Meantime the volume of output of factories had increased by over half, aided by a much increased overall use of power and an associated rise of 13 per cent in the volume of output per person engaged.
There is no statistical record of the electric power used by factories alone, but electric power used for all commercial and page 424 industrial purposes increased by two-thirds in the ten years. This very rapid rate of growth in the use of electric power seems to be necessary as part of the conditions for the steady increase in production per labour unit1 so often found in modern industry. The mobility, instant availability and general convenience of electric power have enabled manpower to be used more and more effectively.
Apart from wartime or depression interferences, the long-term trend for New Zealand has been, in general terms: labour force increasing 2 per cent a year, electric power usage increasing 8 per cent a year, production per head of labour increasing 2 per cent a year, and volume of production increasing 4 per cent a year. These growth rates are not independent of one another.
In the decade 1937–38 to 1947–48, the number of electric motors used on farms approximately doubled, tending to take over work done by internal combustion engines, which increased in number only 11 per cent in the decade. Agricultural tractors were also coming into their own. There were under 7000 in use in 1937; over 23,000 in 1947. Many tractors were supplied by the United States of America under Lend-Lease, and helped New Zealand farming to play its part in feeding United States forces in the Pacific.
This was the age of mechanisation of farming, with the horse being steadily replaced by the tractor. Better methods and better equipment were becoming generally available and, in spite of rising farm production, there was a slow but progressive decline in the numbers of men required to work on farms.
Meantime household demands for electric power were increasing by leaps and bounds. Households took nearly half of all power sold in 1939 and were increasing in relative importance as power users. Their demand for power had almost doubled by 1946. In households the extra convenience of electric power was increasing its popularity for lighting, cooking, and heating, while new gadgets using electric power were creating their own demand.
Wartime difficulties in obtaining sufficient coal to meet all the demands for it were discussed in Chapter 15. It is probable that uncertainties in the supply of coal played some part in bringing about the movement towards electricity in factories and elsewhere. However, in the main, the movement was part of a longer term tendency for electric power to increase in relative importance.page 425
1 Production per labour unit is commonly called productivity. It is normally increased by better equipment, more power in the hands of each worker, and better methods of work. Productivity is sometimes measured per unit of capital used or per unit of some combination of labour and capital used.