Cyclones and heavy storms are a part of life for the Pacific island nation of Tonga. And in the past, those storms have been able to wipe out the country’s power supply for weeks on end. But many years of investment from ADB and other partners have helped strengthen the country’s power infrastructure. And when Tropical Cycone Harold hit the country in April this year, the country’s power supply was able to hold up extremely well. For the likes of Vaiola Hospital on the country’s main island of Tongatapu, having a reliable power supply is literally a matter of life and death.


This was the destructive impact of April’s Tropical Cyclone Harold.

Here in Tonga, the category-four storm devastated three of the country’s four main islands.

The storm surges, with winds of more than 100 kilometers an hour, tore roofs from homes and buildings, ripped trees from their roots, and damaged crops and water supplies.

But amid the damage, one thing held up impressively well: the country’s power supply.

Tonga Power says just 21-percent of customer service lines required repairs and all customers with no electrical hazards had power restored within four days of the storm.

By comparison, it took five weeks to restore power after Cyclone Gita in 2018.

The overall damage to the network of about $300,000 was also much less than the repair bills from both Gita and Cyclone Ian in 2014.

That’s a success story for Tonga and for the Asian Development Bank.

In the past decade, ADB and its partners have invested almost $30 million in making Tonga’s power infrastructure as resilient as possible to natural disasters.

Setitaia Pasivaka Chen, CEO Tonga Power Limited

The design that was built over the last 10 years and that journey is one of the principles of building back better. So the robustness and resilience of the network that’s been built had been proven over the last couple of hurricanes but certainly because of these projects we’ve seen the benefits shine through over the recent hurricane, which was Cyclone Harold.”

A more resilient power supply is vital for people, businesses, and emergency services here in Tonga and across the Pacific—where natural disasters are a regular part of life.

At Vaiola Hospital on Tonga’s main island of Tongatapu, a power supply that can withstand the heaviest of storms is literally a matter of life and death.

Dr. ‘Ana ‘Akau’ola, Acting Superintendent, Vaiola Hospital

Everything that we do in radiology needs electricity. From the computers that I use to read my x-rays, to the ultrasound machines that we use to perform our ultrasounds, to the CT scanner, to the x-ray radiography that we do, to the mammograms that we perform, all need electricity.”

Dr. ‘Ana said cyclones such as Gita and Ian had put the hospital on emergency generators for days—and they’re not strong enough to power things like x-ray machines or CT scanners.

But the disruption from Cyclone Harold was much smaller.

Dr. ‘Ana ‘Akau’ola, Acting Superintendent, Vaiola Hospital

With the Cyclone Harold, we were off for just one day. That’s a comparison that I use to see that there was a big change. Also, what I noticed is, there was less damages in the powerlines on the roads after Cyclone Harold compared to Cyclone Gita. So yes, there’s a big difference.”

Setitaia Pasivaka Chen, CEO Tonga Power Limited

So Vaiola Hospital being an essential service, it’s expected to have 24-hour supply and certainly with the Nuku’alofa network upgrade invested by the Asian Development Bank … we were able to upgrade that network so as to ensure that even through really bad weather, we know that the system is still reliable

Tonga Power says the next phase of its infrastructure resilience investment will be the completion of network infrastructure on the island of Vava’u … part of the outer island renewable energy project … and the completion of the remaining three areas of the network upgrade project in the capital of Nuku’alofa.

These continuing upgrades will help people across Tonga ride out the next cyclone when it inevitably hits.