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
Overview
National hydro storage continued to increase slightly this week and now sits at 82% of the historic mean for this time of year. There were unplanned outages on HVDC pole 3 this week limiting transfer capability. Customer Advice Notices were issued regarding these outages and can be found here.
In this week's insight we provide a summary of the proposed changes to the 2025 Ancillary Services Procurement Plan, which is currently open for consultation.
Security of Supply and Capacity
Energy
New Zealand hydro storage increased to 82% of the historic mean this week, from 80% the week prior. South Island hydro storage also increased from 80% to 83%, and North Island storage increased from 71% to 74% of the historic mean for this time of year.
National storage continues to sit just below the 10th percentile.
Capacity
National capacity margins were healthy last week, with over 1,000 MW of residual available during all peaks. This is due to high thermal unit commitment for this time of year as hydro storage remains relatively low. The lowest residual was 1,685 MW on the evening of Monday 14 April.
The N-1-G margins in the NZGB forecast are healthy through to mid-June. 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 weekly demand decreased by 12 GWh to 718 GWh last week. This was due to lower demand from Friday to Sunday last week during the Easter weekend break. Demand peaked at 5,496 MW at 6:00pm on Tuesday 15 April.
Weekly Prices
The average wholesale electricity spot price at Ōtāhuhu last week decreased to $287/MWh from $325/MWh the week prior. Wholesale prices at Invercargill peaked at $478/MWh on Tuesday 15 April at 1:00am coinciding with a drop in wind generation. There were some instances of price separation throughout the week. On 15 April, this occurred during a period of low wind generation and southward HVDC transfer. From 17 April to 20 April, unplanned HVDC pole 3 outages contributed to price separation as well as a spike (~$6,500/MW) in South Island reserve prices.
Generation Mix
Wind generation increased to 13% of the mix from 9% the previous week while hydro generation decreased to 44% from 48%. The contribution of thermal generation decreased from 21% to 16% this week as wind generation was high and demand was relatively lower. Geothermal generation increased from 20% to 24% as multiple geothermal plants, which were on outage the previous week, returned to service.
HVDC
HVDC flow was predominantly southward last week with a decrease in hydro generation. There were some periods of northward transfer coinciding with periods of low North Island wind generation and high North Island demand. In total, ~31 GWh was sent South and ~2 GWh was sent North.
There were unplanned outages on HVDC pole 3 this week limiting transfer capability. Customer Advice Notices were issued regarding these outages and can be found here. Due to the outage on 17 April, a Grid Emergency was declared to request more South Island Sustained Instantaneous Reserves (SIR).