11 May 2024
The G4 geomagnetic storm affecting Earth as a result of solar activity has been upgraded to a G5 event.
Transpower has switched off some electricity transmission circuits across the North Island as a precaution to prevent damage to equipment, having earlier switched off some in the South Island.
In order to remove these transmission circuits from service, a series of grid emergency notices have been issued.
At this stage, Transpower does not anticipate any impact on New Zealand’s electricity supply. It held an information briefing for the electricity industry at 1.30pm.
Transpower will continue to monitor the situation and provide updates as required.
More information is available about the solar storm on the websites of space weather prediction centres in Australia and USA:
Explainer:
Coronal mass ejections (CMEs) are explosions of plasma and magnetic fields from the sun that are ejected out into space. Once a CME reaches Earth it causes a geomagnetic storm.
While the impact on Earth usually goes unnoticed by most people as its own magnetic field shields us from the particles, it can cause issues with electricity grids, radio signals and other infrastructure.
In a severe geomagnetic storm, the CME can interact with the Earth’s magnetic field, disrupting it and sending pulses of electric current down conductors like power lines. This can damage equipment. To prevent that from happening and to minimise any impact on New Zealand’s electricity supply, Transpower removes some equipment from service.
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