Email not displaying correctly? View this email in your browser
Current Status as at: 30 April 2019


Controlled storage increased slightly over the week and is currently at 107% of average for this time of year. Inflows to the South Island hydro lakes may rise further due to rain currently passing over the country, although inflows to the North Island’s Lake Taupo are likely to remain below average. National storage is currently at levels that indicate a low risk of shortage this winter.
We are now using a dynamic Electricity Risk Meter for New Zealand and South Island controlled storage, which gives a more accurate picture of the current hydro lakes situation. This will be updated on our website every Tuesday or more frequently when required. For more information on the new Risk Meter, see the previous HRC 101.
We have carried out the monthly update of the Hydro Risk Curves (HRCs) and have forecast them out to December 2020. This month we have added summary information on the latest update to the HRCs (found here) that aims to provide a more accessible summary of the HRC update. This update was done prior to the news that the Pohokura gas field outage will be extended until mid-May, and consequently no reductions to gas fired generation were applied. However, we will be assessing the potential impact of the delay to full production of the Pohokura field in early May and will update the HRCs again if necessary.

Current Situation 

Aggregate New Zealand storage increased over the last week and is at 78% of total storage, this is above the historical average (107% of average) for this time of the year.

Weekly hydro generation over the last 12 months has ranged between 54% and 66% of total generation. Last week hydro generation contributed 58% of total generation.

Hydro Storage Update

Controlled storage remains above average on the New Zealand and South Island hydro risk curves.

Inflows into Lake Taupo over the last week were lower than the historical average for the time of the year however there was a slight increase in North Island storage.

South Island inflows were also lower than the historical average over the last week and storage levels have also increase.
View the latest Hydro Risk Curves  »
Read more about Hydro Storage  »

Generation Mix Update

Generation from non hydro sources are expected to remain at current levels.
Read more about Generation Mix  »

Demand Update

New Zealand electricity usage is about average for this time of the year.
Read more about Demand »

Transmission Update

There was a net HVDC energy transfer to the North Island of 83 GWh last week. 
Read more about Transmission »

Wholesale Prices Update

The spot price, based on available final and interim prices, has averaged $90 per MWh over the last two weeks, this is higher than prices experienced this time last year.
Read more about Wholesale Pricing »

Data Updates

We periodically update the base HRC data curves and the Simulated Storage Trajectory Curves.  The updated files for these are available on the Hydro Risk Curve page.
Data Last Updated
Hydro Risk Curve Data File and Input Assumptions 30 April 2019
Simulated Storage Trajectories and Assumptions 30 April 2019

Next Report

The next scheduled weekly Security of Supply Report is due Tuesday 7 May 2019.

Transpower Website

If you have any queries, please email
You can forward to a friendunsubscribe from this list or update your subscription preferences.