Security of Supply

National hydro storage remains below the 10th percentile of historical positions for this time of year. Below average inflows persisted across the country this week. North Island hydro storage has dropped nine percentage points to 82% of average for this time of year. South Island storage has dropped three percentage points to 74% of average for this time of year. The result is a national storage decline of three percentage points to 75% of average for the time of year (60% of total full). Looking forward, our hydro storage projections are above the watch curve. This assumes material inflows will eventuate based on historic inflow sequences, including those for La Nina years.

Total gas production continues to follow its recent and forecast downward trend, reflecting reduced output from Pohukura which now sits around 122TJ per day (see link to GIC website for further information). There were short unplanned outages at Pohokura and Kupe. Demand averaged 755GWh this week, a small increase on the previous week. Prices averaged $340 at Haywards, a percentage increase of 71% on the week prior.

Last week the total generation mix was 76% renewable and 24% thermal. The mix comprised; hydro 53%, wind 2%, geothermal 20%, thermal (coal/gas) 22%, and co-gen 2%.

Last Friday we hosted a security of supply briefing. Our goal was to inform market participants of the approach we take to managing the security of supply function and provide an overview of the situation heading into winter, including hydro lake levels, demand, climate outlook and gas supply constraints. You can see a recording of the briefing, slides and questions and answers here.

Further information here.

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


Hydro Information

Further information here.

Storage decreased in the North Island and South Island over the last week, with South Island storage at 63% of full and North Island storage at 43% of full.


Market Indicators

Further information here.

Renewable generation over the last seven days was 76% of total generation, with hydro generation accounting for 53% of total generation.

Industry Workshops

We run one to two workshops each year of items that are topical to the industry, below are presentations from the last six years of workshops. The last, 26 February 2021, covered the system operator's approach to delivering its security of supply function.

Policies and Publications

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


Invitation to Comment: Annual Security Assessment Scenarios and Sensitivities Closes 17 March 2021