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
National hydro storage remains well above average at 126% of the historic mean for this time of year. North Island storage continues to be high at 159% of the historic mean, while South Island storage is at 123% of the mean.
Today's insight looks at the Changes to the Electricity Risk Curve Watch and Alert definitions under the recently updated Security of Supply Forecasting and Information Policy (SOSFIP).
Security of Supply and Capacity
Energy
National hydro storage has increased to 126% of historic mean at the end of last week from 120% the week prior. South Island storage has increased from 115% to 123% and North Island storage decreased from 165% to 159%.
Capacity
Residuals were lower than usual during morning and evening peaks most of the last week due to colder temperatures and low wind. The lowest residual of 596 MW occurred during the morning of Friday 19 June.
The N-1-G margins in the NZGB forecast showed tighter spots appearing as we are now in winter; we recommend the industry watch these closely. 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 was steady at 816 GWh for the week due to colder than average mornings continuing from the week before. The highest demand peak of 6,378 MW occurred at 6:00pm on Tuesday 16 June.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $37/MWh from $43/MWh the week prior. Wholesale prices peaked at $116/MWh at Ōtāhuhu at 6:30 pm on Tuesday 16th June, coinciding with high demand and low wind. High prices were observed at Invercargill at 4:30pm Wednesday 17th June, with low prices at North Makarewa and high prices at Tiwai. This was due to a planned outage on one of the North Makarewa to Tiwai lines.
Generation Mix
Wind generation was 11% of the generation mix last week, above its annual average of 9%. Hydro generation contributed 58%, slightly below its yearly average of 60%. Thermal generation was at its annual average of 5% of the mix last week. Geothermal generation remained at its annual average of 23%.
HVDC
HVDC flows last week were predominantly northward with very brief periods of southward flow overnight during periods of high wind. Overall, 147 GWh was transferred north, while 3 GWh was transferred south during the week.