Hydro Lakes Remain Depleted

Low inflows, dry weather and increased demand have kept depleted hydro lakes at a reduced level during the first half of January 2008.

New Zealand’s hydro-electric storage lakes remained consistently below average levels during the first half of January 2008. Daily figures show that lake levels hovered between 85% and 89% of average for the time of year, contrasting sharply with last January when they were consistently above average during the same period.

Dry conditions meant that inflows were well below average on all but one day. Daily demand during the first 15 days of January was generally higher than last year, exceeding last year’s figures on 11 days.

Transfers via the Cook Strait cables were steady at about 4 to 5 GigaWatt hours per day, with south-to-north transfers exceeding transfers southward on all 15 days.

As reported on Wild Land in October, the capacity of the Cook Strait cables to meet demand in either main island was significantly reduced. Three months on, little seems to have been done to ameliorate the situation, with planning for a replacement poorly advanced, and no timeframe for the work to be completed is available. This means that a dry summer will require very close management of hydro resources to maintain stable electricity supplies during winter.

A major seismic event in either the North or South Island or a significant volcanic event in the North Island which takes major generating plant out of service could significantly disrupt electricity supply in the lower North Island and upper South Island while the ability to transfer energy across Cook Strait remains limited.

[Compiled from data supplied by M-co.]

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