Hydro Lakes Remain Below Average

Hydro lake storage remained consistently below average during July 2007 and, despite a month of steady demand with fluctuating inflows, storage ended the month where it began – at 78% of average for the time of year.

New Zealand’s hydro-electric lake storage was at 2103 GWh (GigaWatt hours), 78% of average, at the beginning of July 2007 and ended the month at 1911 GWh, 78% of average for the time of year.

Lake inflows were above average on 15 days, with good inflows during the first eight and last seven days of the month.

Demand exceeded last year’s figures on 16 days, peaking at 126.5 GWh on July 9th during a week when daily demand often hovered about 124 or 125 GWh. Although the peak was slightly lower than June’s heaviest demand day of 132 GWh, July’s average daily load of 116.7 GWh was similar to June’s average daily demand of 114.6 GWh.

Inter-island energy transfers reversed June’s trend, with north-to-south transfers via the Cook Strait cable exceeding the more usual south-to-north on 26 days.

Storage at month’s end was better than the crisis year 1992, similar to last year’s, but lower than storage at the end of July 2004 and 2005. The country has again squeaked through another winter with below average hydro storage. Plots of average storage levels generally show an improving trend from late September as demand eases, and inflows from spring rains and snowmelt replenish the storage lakes.

[Compiled from data supplied by M-co.]

2 Responses to “Hydro Lakes Remain Below Average”

  1. jh says:

    Has electricity generation increased?

  2. Ken says:

    Electricity generation HAS increased, mainly from windfarms which are subject to the vagaries of weather, but a welcome improvement.

    The hydro report is focussed on the base-load capacity in NZ which is not subject to very short-term variation in supply. In that area, little has changed, apart from Whirinaki in Hawke’s Bay coming online within the last 18 months.

    The fact that we are still driving our essential “storage generation” very hard is the key element being monitored by these reports.

    With more “windpower” coming online it is hoped that the storage generation component of our essential supply will be driven less hard.

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