Electricity shortages loom next winter

Lake Tekapo. Picture / Brendon O'Hagan

Concerns are growing about the risk of power shortages next winter as the country's crucial southern hydro lakes fall to near minimum levels.

Hydro lakes provide for 65 per cent of New Zealand's electricity, but a lack of rainfall and snow melt means Lake Tekapo and Lake Pukaki, which together provide most of the country's hydro generation, are almost too shallow to operate.

Yesterday, Tekapo was at 705.05m above sea level, about 3m above the minimum operating level, and Pukaki was at 522.02m, about 4m above the minimum.

"They are unusually low for this time of the year, and all the thermal stations we have got, except one, are running flat out," said independent power consultant Bryan Leyland.

"Unless it rains a lot, we are at reasonable risk of a [power] shortage and we should be preparing for that. Nobody should go into panic mode, but we should all go into precautionary mode."

The high electricity price was a sign of the problems in supply. The current spot price was 13 or 14c, compared with 3 or 4c at the same time last year, Mr Leyland said. "In a normal year, at this time, a combination of spring rains and snow run-off mean that the hydro lakes are filling quite rapidly and quite often you are backing off the thermal generation to avoid spilling of the hydro lakes. We are in a reverse situation.

"We are relying entirely on all those big [thermal generation] units, some of which are 30 years old, operating reliably for the next eight or nine months. If one of them fails, we would have to have unusually heavy rain to compensate for it."

Mr Leyland said energy authorities should be looking at any room for extra generating capacity, while consumers needed to think of potential alternatives.

Meridian Energy spokesman Alan Seay said the situation was a concern but could be turned around within a couple of weeks if decent rainfall came along.

If the situation did not improve in the next couple of months, it would be a problem.

"The concerns do centre around next winter, when we would want those lakes, Tekapo and Pukaki, at their maximum operating levels," he said.

Niwa is expecting dry and warm weather conditions in the South Island lakes area until the end of January.