The Energy Security Outlook (ESO) is a monthly report that helps track how secure New Zealand’s electricity supply might be over the next two years. It uses two key tools, the Electricity Risk Curves (ERCs) and Simulated Storage Trajectories (SSTs), to show how likely it is that we’ll have enough electricity, especially during dry periods when hydro lakes are low.
For more information on how it works and why it matters, we have published an 'ESO 101' document that covers how ERCs and SSTs help forecast electricity risks, what triggers action when supply looks tight, and how extra hydro storage can be used if needed.
April 2026 Energy Security Outlook
- Since our last update the national controlled hydro storage position has increased to 108% of the historic mean at 19 April, with South Island storage at 101%.
- There have been small increases to the risk curves in 2026 and 2027 due to a combination of lower coal and gas availability, scheduled thermal outages later in 2026 and early 2027, and later commissioning of new generation. The lower coal and gas availability is a result of a small decrease in storage levels and reduced gas production forecasts. These are unrelated to the global fuel shortage issue.
- No Simulated Storage Trajectories (SSTs) cross the Watch curve in 2026 or in 2027. This assumes the market supplements the existing coal stockpile at its maximum import capability to maintain increased thermal generation during any extended periods of low hydro inflows.
- Despite the recent above average inflows, particularly in the North Island, the current outlook for the next 35 days from Earth Sciences NZ (formerly NIWA) is for drier than average conditions for the west of the South Island which includes key hydro catchments. As we approach winter 2026, an ongoing focus on hydro storage management and ensuring sufficient backup thermal fuels and capacity remains necessary to mitigate the potential for very high prices.
- Current levels of thermal storage (gas and coal) remain close to their maximum levels. We are engaging with thermal generators to ensure we receive timely information should there be a need to modify our assumptions as a result of the global fuel supply situation.
The graphs below compare New Zealand and South Island controlled storage to the relevant Electricity Risk Status Curves.
Image
Image
Related Files
Energy Security Outlook Data Files
Assumptions and Update Logs
- Scenarios
- Historic Logs