Our Market Operations Weekly Report contains the latest information about the electricity market, including security of supply, wholesale price trends and system capacity.
It is published every Tuesday. Click here to receive the report via email every week.
If you have any comments or questions please contact the Market Operations Team at [email protected].
Latest Report / More Information
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MO Latest Update.pdf
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Current Storage Positions
Security of Supply and Capacity
Energy
New Zealand hydro storage dropped to 66% of the historic average last week. North Island hydro storage dropped from 55% to 41% of the historic mean for the time of year, and South Island storage decreased from 73% to 70%.
Although hydro storage is declining to historically low levels, the electricity risks also shift downward at this time of year, as spring/summer inflows are expected along with lower demand over summer.
Capacity
Margins remained healthy last week reflecting high thermal commitment due to low hydrology and sustained energy prices. Residual generation was over 500 MW over the peaks during the week.
We issued a revised NZGB CAN two weeks ago that highlighted potential N-1-G shortfalls on all weekdays from 12 July through to the end of the month. Some of these have been resolved but potential shortfalls remain from 19 July to the end of the month. The potential shortfalls on 23 and 25 July are now the largest at -155 MW each. This is due to a combination of high demand over the same period last year and multiple generation and transmission outages. From 1 August, NZGB will
start using Yes Energy's (formerly Tesla) probabilistic load forecasting model in its calculations.
We recommend that participants consider the flexibility of planned outages and whether the start/end time of the outages can be rescheduled away from the peaks. We also recommend avoiding scheduling further outages during this period
that may reduce generation margins. The latest NZGB report is available on the NZGB website.
Electricity Market Commentary
Weekly Demand
Total demand remained at 870 GWh last week. This is the highest level for this time of year since 2021. Demand peaked at 6,563 MW on the morning of Friday 12 July, 278 MW lower than last week's peak.
Weekly Prices
Average wholesale energy prices remained high last week, with the average wholesale price at Ōtāhuhu increasing from $304/MWh to $332/MWh. High average prices are in line with lower hydro storage, highly priced energy offers and
high thermal unit commitment. Wholesale prices peaked at $529/MWh at Ōtāhuhu over the evening peak on Wednesday 10 July.
Generation Mix
The average renewable percentage of the generation mix decreased by 3% to 77% last week driven by a decrease in wind generation from 8% to 6% of the mix.Thermal generation increased last week from 18% to 21% offsetting wind generation in the first half of the week and hydro generation in the second half of the week; the 186 GWh of thermal generation was the highest since winter 2021 with all three Huntly Rankines running from Thursday onwards as well as Huntly Unit 5. Hydro and geothermal generation remained steady at 51% and 20% of the mix respectively though hydro backed off during the second half of the week as wind generation increased. Hydro generation is well below the 52 week average of 57%, reflecting limited inflows to catchments in the last few months.
HVDC
During the first half of last week, HVDC flow was northward during the day and southward overnight. Flow was predominantly southward during the second half of the week as demand dropped and wind generation picked up in the North Island. In total, 26 GWh was sent south and 14 GWh sent north last week.
A reminder that there are planned HVDC outages for Pole 3 on 20 July between 07:30am and 12:00pm and Pole 2 between 13:00pm and 17:00pm. There is also live line work on Benmore Haywards 1 between 08:00am and 16:00pm on 18 and 19 July.