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Current Status as at: 20 November 2018
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Recent heavy inflows have relieved the immediate increased focus on security of supply, however, we are still closely monitoring the situation due to the ongoing outage at Pohokura, continued dry conditions in the North Island, and the natural volatility of inflows during summer months. Over the next 8-10 weeks we expect the risk of shortage due to hydro storage to remain low (though, in the unlikely event of major equipment failures the situation could deteriorate) and the Risk Meter is currently set to normal.
Last week we updated the Hydro Risk Curves (HRCs) to account for the current Taranaki Combined Cycle Power Station outage. This builds on previous updates to include longer term outages that we have confirmed cannot be realistically deferred and that will have a material impact on security of supply. Including additional plant outages will always increase the HRCs in the months leading up to the outage as well as the month of the outage.
We are also working on a further HRC update for early December to include a number of pieces of new information:
- Updated demand forecast and supply-side information (i.e. generation output) as part of our preparation and analysis for the security of supply annual assessment. This year the underlying demand forecast has decreased for 2019 and 2020 which will lower the HRCs. However, we are also looking to include previously unaccounted for embedded generation, and potentially household solar generation, on the supply-side. This is unlikely to have a material impact on the HRCs but will inflate the reported demand numbers as we had previously not accounted for demand served by this source of generation.
- Updated information regarding the Huntly Unit 1 outage, and return to service of Huntly Unit 2. Huntly Unit 2 has been made available for the last two months of the Huntly Unit 1 outage. We will account for this in the HRCs, and as such it is likely to decrease the HRCs materially in the first quarter of 2019.
- We will be including any findings from our verification of thermal fuel consumption. We do not know what, if any, impact this will have on the HRCs at this stage, but if we identify any physical fuel constraints then these will likely manifest in increases to the HRCs.
In addition to these updates, we will also include our usual update of outage information.
As this is a substantial update, we expect to publish new HRCs in early December.
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Aggregate New Zealand storage increased over the last week and is at 55% of total storage, this is below the historical average (95% of average) for this time of the year.
Weekly hydro generation over the last 12 months has ranged between 48% and 71% of total generation. Last week hydro generation contributed 71% of total generation.
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Controlled storage remains below 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 an increase in North Island storage.
South Island inflows were also higher than the historical average over the last week and storage levels have also increased.
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Generation from non hydro sources are expected to remain at current levels.
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New Zealand electricity usage is about average for this time of the year.
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There was a net HVDC energy transfer to the North Island of 94 GWh last week.
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The spot price, based on available final and interim prices, has averaged $131 per MWh over the last two weeks, this is higher than prices experienced this time last year.
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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 |
15 November 2018 |
| Simulated Storage Trajectories and Assumptions |
16 November 2018 |
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The next scheduled weekly Security of Supply Report is due Tuesday 27 November 2018.
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