Energy Security Outlook

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.

Energy Security Outlook 101

March 2026 Energy Security Outlook

Energy Security Outlook - March 2026.pdf (PDF 3.37 MB)

Since our last update the national controlled hydro storage position has dropped to 103% of the historic mean at 22 March, with South Island • storage at 97%.
There have been reductions to the risk curves in mid-2026 and 2027 due to increased gas in storage, contracted gas reallocation from some industrial users to power generation, and newly modelled wind and solar projects coming online in 2027.
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.
NIWA has forecast in their seasonal climate outlook that below-normal rainfall is most likely for the west of the South Island over the next two months, 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.