Market Operations Weekly Report

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 Market.Operations@transpower.co.nz.

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More info on security of supply and capacity

Current Storage Positions

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Overview

National hydro storage continued to decline over the past week, largely due to low inflows. It has now fallen to 86% of the historic mean for this time of year.

In this week's insight we look at causes of the rapid decline in hydro storage since the start of 2025. 

Security of Supply and Capacity

Energy

New Zealand hydro storage decreased from 89% to 86% of the historic mean last week with continued below average inflows. South Island hydro storage dropped from 87% to 84%, and North Island storage dropped from 110% to 107% of the historic mean for this time of year.

Storage in the Waiau catchment (lakes Manapōuri and Te Anau) is extremely low. More information about our planned actions to manage the issue is on our website.

Capacity

National capacity margins were healthy last week, the lowest being 953 MW on Tuesday morning with low wind generation. Peak load was relatively low as is usual for summer, and thermal unit commitment was high for this time of year as hydro generation reduced with declining storage.

The N-1-G margins in the NZGB forecast are healthy until late April. 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 increased by 7 GWh to 732 GWh last week, roughly in line with typical load at this time of year based on recent years. Demand peaked at 5,365 MW at 5:30pm on Monday 17 February.

Weekly Prices

The average wholesale electricity spot price at Ōtāhuhu last week decreased to $242/MWh from $283/MWh the week prior. This was significantly higher than the Benmore average price of $194/MWh, with price separation over the weekend during the HVDC bi-pole outage. Wholesale prices at Ōtāhuhu peaked at $450/MWh on Sunday 23 February at 4:30pm. There was also a period of higher outage, when there was high North Island wind generation, resulting in high prices for fast instantaneous reserves (FIR) in the South Island. 

Generation Mix

The average renewable percentage last week increased to 81% with increased wind generation. Wind generated 10% of the mix, up from 5% the week prior. Thermal generation decreased to 17% of the mix from 19% the week prior. Hydro generation contributed a very low 47% in line with declining hydro storage, and geothermal contributed 24% of the generation mix. 

HVDC

HVDC flow was mostly southward last week for the first time since September. In total, 8 GWh was sent north and 17 GWh was sent south. The HVDC also reached its highest southward transfer rate since August with 590 MW sent south during the 12:30 am trading period on Thursday 20 February. Net southward flow is increasing as hydro storage declines and thermal unit commitment increases.

HVDC transfer was limited by a pole 3 outage beginning on Thursday 20 February and a bi-pole outage on the weekend. Pole 2 remains on outage and is scheduled to return on 8 March. We issued a CAN containing the details here.