Security of Supply

National hydro storage now sits below the 10th percentile of historical positions for this time of year. However, based on current lake levels at the time of reporting, the risk to security of supply remains low. This is represented by the current storage position relative to our watch curve.

Looking forward, our hydro storage projections are above the watch curve. This assumes material inflows will eventuate based on historic inflow sequences, these include La Nina years. If we do not receive material inflows in the next few weeks, or more thermal generation, then we may see our hydro projections (not hydro storage levels) cross the 1% risk curve which is about 600GWh above the watch curve during winter.

Below average inflows persisted across the country this week. North Island hydro storage has dropped eight percentage points to 91% of average for this time of year. South Island storage has dropped five percentage points to 77% of average for this time of year. The result is a national storage decline of three percentage points to 78% of average for the time of year (64% of total full).

NIWA’s climate outlook forecasts a continuation of below average rainfall in the Southern catchment region between February and April 2021; note forecast confidence is low, and recognises ex tropical cyclones can hit New Zealand during this time frame bringing large rainfall events. More information from NIWA on this climate outlook can be found here.

Total gas production continues to follow recent slow downward trends, reflecting reduced output from Pohukura. Pohukura output now sits at 124TJ per day  (see link to GIC website for further information). In contrast, Ahuroa gas storage has increased from 5PJ in November and now sits at 6PJ.

Genesis have bought on a third Rankine at limited capacity which is dual fuelled. The national coal stockpile was last reported to be sitting at 496kt; the equivalent of 10.6PJ of energy. This is high compared to recent years.

Demand averaged 746GWh this week, a small increase on the previous week. Prices averaged $249 at Haywards, an increase of $52 on the week prior.

Last week the total generation mix was 77% renewable and 23% thermal, comprising: hydro 52%, wind 5%, geothermal 19%, thermal (coal/gas) 21%, and co-gen 2%.

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 66% of full and North Island storage at 50% of full.


Market Indicators

Further information here.

Renewable generation over the last seven days was 77% of total generation, with hydro generation accounting for 51% 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.