AWARDS FINALIST: Transpower – Space weather - from invisible risk to national resilience

Transpower and the Solar Tsunamis Endeavour Programme have developed a proven strategy to manage the "invisible threat" of space weather, which has paid off across multiple geomagnetic storms in the past two years.

Coronal mass ejections - massive clouds of plasma that explode from the sun into space - can trigger temporary disturbances called geomagnetic storms if directed at Earth.

They can create geomagnetic-induced currents in electrical transmission networks globally and have previously damaged transformers and disrupted electricity supply worldwide, including on New Zealand's grid in 2001.

Transpower and the University of Otago-led Solar Tsunamis Endeavour Programme's end-to-end response system for solar storms was first activated during the G5 Gannon storm in 2024 and helped the grid ride through the extreme space weather events.

The May 2024 event was the most significant geomagnetic event to affect Earth in more than 20 years and Transpower took 18 selected circuits out of service nationwide as a precaution.

It says the measures reduced damaging stray currents flowing through critical transformers by up to 50 per cent, with no reported consumer electricity supply interruptions.

The mitigation response was repeated in November last year when a G4 solar storm approached New Zealand. Transpower issued a grid-emergency notice temporarily removing some South Island circuits from service to protect equipment.

Programme development

Transpower says the programme - a finalist in this year's Energy Excellence Awards - was developed through collaboration between Transpower, researchers from the University of Otago's Solar Tsunamis Endeavour Programme and electricity-sector participants through the Electricity Space Weather Working Group.

The programme combines geomagnetic monitoring, scientific modelling, operational procedures, industry coordination and public communications to manage the risk that extreme solar storms can pose to New Zealand's electricity infrastructure.

A key component is a long-term dataset of geomagnetically induced current measurements collected across the national grid.

It has monitored and archived neutral current observations for more than two decades and has expanded monitoring to more than 100 transformers across 35 substations by 2026.

Transpower says this information has been used to identify vulnerable assets, validate network models, assess extreme-event scenarios and develop mitigation plans that are embedded in operating procedures and supported by control-room training.

Formal processes

Beyond technical measures, the programme established formal processes linking scientific updates, operational assessments, industry notifications and public communications.

Transpower also worked with the National Emergency Management Agency and the Electricity Authority on response planning, public information and sector exercises intended to improve preparedness for extreme space weather events.

It says this creates a common operating picture across operators, regulators, emergency managers, sector participants and the public.

The programme has been further refined through both planning activities and live events, and the mitigation measures, operational escalation processes and communication procedures are now embedded within Transpower's readiness and response framework.

Transpower says its present capability provides a repeatable process for monitoring space weather threats, assessing network impacts and implementing protective actions when required, while maintaining electricity supply wherever possible.

The annual Energy Excellence Awards will be held in Wellington on 19 August. The Innovation in Energy Award is sponsored by Fujitsu.