Security of Supply
National hydro storage dropped slightly this week to 101% of average for the time of year (65% of full),with average inflows seen over the week.
North Island storage increased one percentage point to 71% of historical average, and South Island storage decreased one percentage point to 105% of historical average.
National weekly demand rose 38 GWh (five percent)on the previous week. With a cold Southerly making its way over the country, load on Sunday was particularly high for a weekend - up 12% on the previous Sunday. Peak load on Sunday was 6,380 MW, with a weekday peak load of 6,552 MW on Tuesday at 18:00.
Total generation was 892 GWH this week, with hydro generation making up 59%, and thermal 16% of the generation mix. Wind generation was high at 39 GWh, or 4.4% of the mix.
The average price at Haywards was $155/MWh, up 20% from $130/MWh last week. Prices were fairly steady, with a few deviations around a clear base price of $140-$150 /MWh. Highest prices of around $315 /MWh occurred during peak periods on Monday and Thursday mornings and Sunday evening.
Constraints on HVDC transfer on Thursday evening and Friday led to inter-island price separation, with Benmore prices falling as low as $43/MWh on Friday afternoon. These constraints were due to weather related salt contamination of Pole 2 at the end of the undersea cable, and the subsequent removal of this pole from the market on Friday for cleaning.