Late Reprieve for Hydro Lakes

Above average inflows during the past week have given New Zealand’s hydro storage lakes a much-needed boost.

New Zealand’s hydro-electric lake storage plunged below average for the time of year late in February 2007. Below average in-flows during summer and autumn continued the steady depletion which saw storage pass below last year’s levels – a year in which supply shortages became a concern – toward the end of April.

However, during May 2007, weekly inflows have turned the corner, trending back toward average values, and then passing above average for the first time this year. While total storage still remains below average for this time of year, storage has now returned to where it was at this time in 2006.

Interim figures published for Friday 25th May 2007 show that hydro storage was at 2317 Gigawatt hours (GWh), 80% of average for this time of year.

The late recovery suggests that electricity supply concerns will have eased. While storage is not better than last year’s, when there were concerns that shortages might occur during the colder winter months, it can be hoped that new generating capacity will allow the country to squeak through this winter. Another close shave for the energy supply industry.

Energy managers have been closely managing hydro storage during May, maintaining declining southern lakes with north-to-south transfers via the Cook Strait cable. During the first 3 weeks of May, north-to-south transfers exceeded south-to-north on 12 days out of 19.

[Compiled from data supplied by M-co]

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