Corrosive ash from massive 2022 Hunga Tonga-Hunga Ha’apai eruption causes power crisis in Tonga

Corrosive ash fallout from the massive eruption of Hunga Tonga-Hunga Ha’apai volcano last year has triggered a series of power outages on Tonga’s main island, Tongatapu, beginning September 2022. Tonga Power, the island’s electricity provider, has termed the situation a “crisis” due to the unprecedented damage to the High Voltage Aerial Bundled Cabling across the island.

On Tonga’s largest island, Tongatapu, residents have been grappling with power outages since September 2022, an unforeseen consequence of last year’s colossal eruption of the Hunga Tonga-Hunga Ha’apai volcano. The corrosive ash from the eruption has wreaked havoc on the electrical infrastructure, particularly affecting the High Voltage Aerial Bundled Cabling system installed before the eruption. The cabling, designed to withstand strong cyclone winds, has been corroded by the solidified ash, causing significant damage to the internal wiring.

According to Tonga Power, the electricity provider on the island, this corrosion has thus far caused four notable power outages. The most affected region is the Nuku’alofa district, where many faults have occurred, impacting not only the district but also neighboring villages connected to the same feeder. The corrosion problem is exacerbated by the heat from sunlight and the cable itself, resulting in short circuits across Tongatapu’s network.

At a recent press conference in Nuku’alofa, officials from Tonga Power, including Business Manager Andrew Kautoke and Chief Executive Finau Moa, shed light on the extent of the damage. They exhibited damaged wires, explaining how the abrasive ash sticks to the wires, grazing them until the insulation is eaten away, leading to a short circuit. Kautoke termed the situation as a “crisis”, emphasizing that this is one of the first times the network has experienced such a problem, especially from volcanic ash impact.

Tonga Power teams are currently surveying the damage, and more outages are anticipated in the near future. The damaged wires will need replacement, and meticulous cleaning of all power line cables is crucial to prevent further erosion and ensure a reliable power supply.

The eruption that caused this ongoing crisis started at 15:20 UTC on January 14, 2022, with a significantly larger eruption following at 04:14 UTC on January 15 (VEI 5 – 6). The latter sent ash clouds as high as 58 km (36 miles) into the mesosphere, marking the highest-known eruption column in history and the largest ever observed eruption with modern instrumentation.

The eruption displaced 6.6 km³ (2.5 mi³) of seawater, 90 m (300 feet) in amplitude, with a length of 12 km (7.5 miles).

It not only caused massive disruptions in Tonga but also led to tsunami warnings, evacuation of nearby islands, significant damage to regional infrastructure, and changes in local coastal geography.

References:

¹ Addressing power outages due to HTHH asfhall impact on HV ABC network infrastructure – Tonga Power LTD – October 11, 2023

² Hunga Tonga-Hunga Ha’apai volcano ash causing power outages in Tonga – utility provider – NZ Herald – October 16, 2023

Featured image: Tonga Power