Hydro Lakes Rise Dramatically

Hydro-electric storage lake levels rose dramatically during December 2010, according to provisional figures released by WITS Free To Air.

Provisional data released by WITS shows that New Zealand’s hydro lake levels grew by a staggering 1500 GigaWatt hours (GWh) during December 2010.

At the beginning of the month, storage stood at 2885 GWh, 109% of average for the time of year. By month’s end this had risen to 4392 GWh, 149% of average. Inflows were below average until December 17th. The following day inflows increased dramatically, rising to 300% and 400% of average from December 21st to the 23rd. The 30-day average of inflows for the month was 888 GWh, 148% of average for the time of year.

During 2008 and 2009, hydro storage was mid-way between 3000 and 4000 GWh at the same time. By comparison, the crisis years of 1992 and 2007 started the year with lakes below 2000 GWh and 3500 GWh respectively. Throughout 1992, lake levels were consistently below average, leading to an energy shortage, while in 2007 storage plunged below average in February and the dry conditions kept it there throughout winter leading to worries over a shortage of energy from hydro generation.

Whilst the provisional figure of 4392 GWh is a good sign for 2011, it is worth noting that a dry summer and winter can rapidly erode this advantage. South Island inflows typically peak during spring, while North Island lakes gain most of their water during winter. This year’s weather patterns will be crucial in maintaining this advantage.

[ Compiled from data supplied by NZX and WITS Free to Air. ]

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