Security of Supply

At a national level, hydro storage continues to be below the tenth percentile for this time of year. However, risk to security of supply remains low due to thermal generation availability and declining risk curves from now until summer. 

Hydro storage in the South Island continued to decrease over the past week, however only by 1% due to some inflows and now sits at 79% of average. North Island hydro storage decreased by 6% to sit at 68% of average. North Island storage currently sits at 32% of full, while this is low, storage is up considerably since this time last month where storage sat at 22% of full.  

Following on from Genesis’s announcement last week to make available a third Rankine unit if required, the unit was observed in operation over the weekend during an unplanned outage at the Kupe gas field. 

Thursday’s news on the closure of the Tiwai Point aluminium smelter will have significant implications to security of supply, we will be updating our analysis accordingly. While current ERC’s do not currently factor in this closure, our annual security of supply assessment [ pdf 5.59 MB ] which looks at a 10 year horizon does contain a scenario for this outcome.

Nationally, weekly electricity demand increased by 6.1% to 861 GWh. 


Security of Supply – Outlook to 2030: Workshop 28 July 10 am – 12 pm

Update: This workshop will now be held at Transpower's Wellington office with an option to participate online. We look forward to seeing you there. Further information is available here.

Electricity Risk Curves

Further information here.

New Zealand and South Island storage are both in the Normal range.


Hydro Information

Further information here.

Storage increased in the North Island and decreased in the South Island over the last week, with South Island storage at 58% of full and North Island storage at 32% of full.


Market Indicators

Further information here.

Renewable generation over the last seven days was 75% of total generation, with hydro generation accounting for 60% of total generation.


Policies and Publications

Includes information on the Annual Assessment and Transpower policies related to Security of Supply: the SoSFIP, EMP, and SOROP.


Currently no consultations.