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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Current Storage Positions
Overview
New Zealand hydro storage increased to 121% of the historic mean last week and currently sits just below the 90th percentile.
This week’s insight looks at the high renewable share observed over the last two weeks and how it compares to historical data.
Security of Supply and Capacity
Energy
Inflows to catchments continued last week resulting in national hydro storage increasing to 121% of the historic mean from 115% the week prior. South Island hydro storage increased from 112% to 118% of historic mean and North Island storage increased from 135% to 143%.
Capacity
Capacity residual margins were relatively healthy for most of last week, however residuals dropped slightly lower during some morning peaks. The lowest residual of 446 MW occurred during the morning peak on Friday 17 October during a period of low wind generation.
We continue to monitor capacity closely during the spring shoulder season despite decreasing demand. Outages, reduced thermal unit commitment, and the possibility of cold snaps or large swings in wind generation mean that capacity can be tight despite much lower peaks than in winter.
The N-1-G margins in the NZGB forecast are healthy through to mid December. Within seven days we monitor these more closely through the market schedules. The latest NZGB report is available on the NZGB website.
Electricity Market Commentary
Weekly Demand
Total demand last week increased from 750 GWh the week prior to 762 GWh, reflecting slightly colder temperatures and a return to typical levels of demand after the school holiday period ended. Total demand is similar to that observed at this time of year over the past three years. The highest demand peak at 5,669 MW occurred at 7:30 am on Wednesday 15 October.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $26/MWh from $34/MWh the week prior in line with increasing hydro storage and higher than average wind generation. Long periods of very low pricing occurred during the weekend.
Wholesale prices peaked at $419/MWh at Ōtāhuhu at 7:30am on Friday 17 October during a period of low wind and high demand which meant highly priced thermal generation was required to help supply the morning peak.
Generation Mix
Renewable generation remains high and contributed 98% of the generation mix last week. Wind generation decreased its share of the mix from 16% to 13% of the mix, while remaining above its average contribution of 9%. Hydro generation was above average and increased to 62% of the mix from 59% the week prior. Thermal generation remained low at 1% of the mix reflecting high hydro and wind generation and thermal outages including Huntly unit 5. The geothermal share increased to 22% of the mix, close to its annual average level of 23%.
HVDC
HVDC flow last week was predominantly northward with the exception of some brief periods of overnight low southward flow. These periods coincided with periods of high wind generation and lower North Island demand. In total, 29 GWh was transferred north and 3 GWh was transferred south.
SOSFIP Consultation Open
Consultation on a draft amendment to the System Operator Forecasting and Information Policy (SOSFIP) is now open. The closing date for submissions is 5pm on Tuesday 4 November 2025, with cross-submissions due by 5pm on Tuesday 11 November 2025.