Eye on electricity
Space weather and the power system
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- Wholesale
Space weather has the potential to cause significant disruption to New Zealand’s electricity system. While rare, severe solar storms that reach Earth may affect the power network and system reliability.
This article outlines what space weather is, how it can affect the power grid, how these risks are managed and the role the Electricity Authority Te Mana Hiko plays in supporting system resilience.
What is space weather?
Space weather refers to the flow of particles and energy released by the Sun, which travels through space and can reach Earth. Space weather is continuous, but its effects are strongest when the Sun releases large bursts of energy and material, known as coronal mass ejections (CMEs).
As the Sun moves through its most active phase in its 11-year cycle, New Zealand has experienced several solar storms in recent years, including in May 2024 and November 2025. Not only do these storms produce the auroras sometimes visible in our night sky, but they can also impact a range of important infrastructure, including our power grid.
How solar storms can affect the power grid
Solar storms can distort Earth’s magnetic field. When a magnetic field changes around electrical conductors, it causes the electrons inside those conductors to move, creating an induced current. During strong solar storms, these induced currents can flow through the Earth’s surface and into the power grid.
When a solar storm is intense enough, the resulting currents can damage critical equipment, such as transformers. In severe cases, this could cause widespread power outages.
In New Zealand, grid equipment has been impacted by solar storms before. For example, a transformer in Dunedin failed during a solar storm in November 2001.
Protecting the power grid from solar storm impacts
Space weather is monitored in real time via satellites, which can provide between 15 minutes and one hour advance warning before a solar storm reaches Earth. This lead time enables the power grid to be reconfigured before the solar storm hits, reducing the risk of damage to equipment and disruption to consumers.
For example, between 12 and 13 November 2025, three consecutive Earth-directed CMEs were released from the Sun. Transpower issued a grid emergency notice and temporarily removed three South Island circuits and one transformer from service to decrease the flow of induced currents.
To prepare for the impact of severe solar storms, Transpower may need to reconfigure the grid by disconnecting certain assets and lines. If this occurs, Transpower issues grid emergency notices to inform industry participants.
Building resilience through preparation
To strengthen preparedness, the Electricity Authority and Transpower are running an Industry Exercise in May 2026 that will simulate a major hypothetical space weather event affecting New Zealand’s power system.
The exercise will allow the System Operator and industry participants to rehearse and test their operations and communications across the sector. By practicing how the system would respond to a major event, the exercise helps build capability, identify areas for improvement, and support a secure and resilient electricity system.
There is still time for electricity market participants to register for the Industry Exercise and we encourage all participants to take part. Register for the Industry Exercise
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