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 has increased from 110% to 112% of the historic mean for this time of year. This continues to be largely driven by North Island hydro storage where Taupō is at 228% of the historic mean.
This week’s insight discusses a period of inter-island price separation resulting from an interesting least cost solution from the market solver (SPD).
Security of Supply and Capacity
Energy
National hydro storage has increased to 112% of the seasonal mean at the end of last week. South Island hydro storage has remained the same at 104%. North Island storage increased from 208% to 228%.
Capacity
There were periods of lower than usual residual across last week during peak morning and evening periods resulting from very low wind periods. Thermal peaking units were switched on to meet national demand at these times.
The N-1-G margins in the NZGB forecast are healthy through to mid May. 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 continues to increase as we creep into the beginnings of winter. Last week demand increased from 743 GWh to 788 GWh. The highest demand peak of 6,108 MW occurred at 6:00pm on Tuesday 21 April.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week was $101/MWh, increasing from $63/MWh the week prior. Wholesale prices peaked at $429/MWh at Ōtāhuhu at 7:30am on Thursday 23 April with demand increasing and a tight offer stack. This happened a few times during peak demand periods across the week.
There were several periods of price separation across the week notably on Monday and Tuesday which we discuss in this week's insight.
Generation Mix
Wind generation decreased from 14% to 7% of the mix. Hydro generation increased from 51% to 59% of the mix. Thermal generation remained at 6% of the mix despite the peak periods bringing on additional units. Geothermal decreased from 27% to 25% of the mix.
HVDC
HVDC flow was mostly northward with the increased hydro generation this week to support the increased North Island demand and low wind generation. There were some periods of South Island transfer overnight when wind was moderate
early in the week. In total, 77 GWh was transferred north and 14 GWh was transferred south. HVDC transfer was limited over the weekend due to a series of outages including a bi-pole outage on Sunday.
Surveys and Engagement
We have published our draft 2026 Security of Supply Assessment (SOSA) for consultation. Submissions close on 21 May. This provides a 10-year assessment (2026 to 2035) of the balance between supply and demand in the New Zealand
electricity system.
Our Annual System Operator Participant Survey remains open to provide an opportunity for participants to set out their expectations and help us understand how we are performing the System Operator service. If you have not received the survey but would like to have your say, you can complete it here. The survey closes 30 April 2026.