‘Solar heating of water could save $26M’

Press, 8 May 1978, Page 34

‘Solar heating of water could save $26M’

PA Hastings A solar water heater costing between $6OO and $9OO would enable larger households to save about $5O a year on electricity at present prices, said the Minister of Energy (Mr Gair). “This means it would take about 10 years for a solar unit to pay for itself at present domestic electricity rates,” he said.

Mr Gair was speaking at the official opening of Morrison Industries, Ltd’s new I solar heating production plant at Hastings. “But electricity is at present priced below its incremental cost and it is one of life’s more certain prospects that the real cost of energy will continue to rise over the next few years. “Such a trend would, of course, serve to reduce the pay-back period for solar installation.”

Mr Gair said the average consumption of electricity for domestic water heating was at present estimated at 4000 kW a year. “Tests indicate that in a favourable situation with good orientation to the sun, minimal shading, and thermostat not set too high, solar lyater-heaters with four square metres of collector area of good efficiency can reduce the amount of energy

purchased for the purpose of water heating by up to 50 per cent,” he said. This did not vary by more than a few per cent anywhere in New Zealand, the Minister said. “At a national level there are about 515,600 households which could each save 2250 kW a year with the use of solar water heaters.”

This would represent 6 per cent of the total electricity used at present, he said. “The annual value to the nation of the power saved would be about $26.5M a year.

“But because the electricity used for domestic water heating is in most cases controlled, and therefore switched off at peak periods of consumption, solar water heaters can make little contribution to reducing winter peaks and therefore reducing the need for generating capacity. “Also, winter peaks occur on cold, wet afternoons when the solar collectors would hardly be functioning,” Mr Gair said. Apart from domestic use, solar water heaters could also have a useful part to play in providing hot water in the lower temperature range for hotels, motels, hospitals, dairy sheds and freezing works, he said.