Hydro Lake Storage Continues to Decline

The levels of New Zealand’s hydro-electric storage lakes declined further during February 2007, continuing the trend set in December 2006. By month’s end, storage was 94% of the average for the time of year, having slid to below average levels on the 21st.

At the beginning of February 2007, New Zealand’s hydro lake storage stood at 3475 Gigawatt hours (GWh), 110% of the average for the time of year. By month’s end this had slid to 94% with storage at 2994 GWh reflecting the lack of rain in much of the country.

The below average inflows noted during January were even worse during February with above average inflows being recorded on only 3 days. The low rainfall in lake catchments was reflected in a steady downward trend which varied between 66% and 158% of average inflows during week 1, 62% – 106% during week 2, 55% – 67% during week 3 and 55% – 62% of average during week 4.

Despite the declining water levels, storage was still consistently above average levels recorded at the same time last year when it was feared that winter-time power shortages might occur. However, as storage levels declined during February, the margin above last year’s levels also declined. At the beginning of February storage was 110% of average, compared with 82% in 2006. By the end of the month, the 2007 value was 94% compared with last year’s 74%.

The narrowing margin over last year’s storage may become significant if the dry weather conditions continue throughout March.

[Compiled from data supplied by M-co.]

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