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 above average, with levels at 113% of the historic mean for this time of year. North Island storage continues to be exceptionally high at 208% of the historic mean, while South Island storage is close to average at 106% of the mean.
This week we're starting a three-part deep dive series on the electricity sector's readiness for winter. Today's part looks at installed generation vs peak capacity risk.
Security of Supply and Capacity
Energy
National hydro storage remains at 113% of historic mean at the end of last week. South Island storage is steady at 105% and North Island storage decreased from 225% to 208% with lower than average inflows for North Island last week.
Capacity
Residuals were healthy during morning and evening peaks last week. The lowest residual of 749 MW occurred during the morning of Friday 15 May, which coincided with the highest demand peak of the week.
The N-1-G margins in the NZGB forecast remain healthy, but are trending downwards into winter with tighter spots appearing; 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 increased from 764 GWh to 795 GWh for the week due to colder than average mornings. The highest demand peak of 6,058 MW occurred at 7:30am on Friday 15 May.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week increased to $69/MWh from $38/MWh the week prior. Wholesale prices peaked at $213/MWh at Ōtāhuhu at 7:30am on Friday 15 May, coinciding with the highest demand peak of the week.
Generation Mix
Wind generation has decreased from 14% to 6% of the generation mix last week, lower than its yearly average of 10%. Hydro generation has increased from 53% to 59% of the mix and thermal generation remained at 6%, Geothermal generation was unchanged at 25%, continuing to sit above its annual average of 23%, as seen in recent weeks due to the additional geothermal capacity at Ngā Tamariki and TOPP2.
HVDC
HVDC flows last week were predominantly northward with very brief periods of southward flow overnight. Overall, 113 GWh was transferred north, while 5 GWh was transferred south during the week.
Consultations and Engagement
SOSA
We received six submissions to our draft SOSA 2026 consultation, which have been published on the consultation page. We are now in a period for cross submissions which closes this Thursday 21 May. The SOSA provides a 10‑year outlook (2026–2035) on supply‑demand balance to support security of supply risk management and investment decisions.
Emergency Reserve scheme
Expressions of interest are also open until Wednesday 20 May for an industry co‑design panel to support the development of the new Emergency Reserve ancillary service, enabled by recent Electricity Authority Code changes.
Draft Policy Statement
Consultation is open on our draft Policy Statement amendment proposal with submissions due by Thursday 4 June.
The Policy Statement describes the policies and processes the System Operator uses to meet the principal performance obligations (PPOs) in the Code for maintaining a stable and resilient power system in real-time, and to manage technical compliance and conflicts of interest.