One of the largest solar farms in the South Pacific
From panels to impact:
Annual Energy Production: ~11MWh/ yr
Economic value: Offset 18% of Tonga’s diesel generation, powering > 10,000 households
Environmental value: ~7,370 t carbon offset/ yr
Deployed by:
6.9 MWp of solar energy
Across Tonga’s 170 islands, diesel met up to 90 per cent of energy needs, leaving the Kingdom exposed to volatile fuel prices and long supply chains. The Tongatapu Solar Farm shows what Pacific island solar can deliver at utility scale. Built under a power purchase agreement (PPA) between Sunergise New Zealand Limited, a Todd Corporation company, and Tonga Power Limited, with support from the Asian Development Bank, it was the largest solar farm in the South Pacific when commissioned in 2022. It offsets 18 per cent of Tongatapu’s diesel generation, a key step towards Tonga’s National Renewable Energy Roadmap and energy independence.
The Challenge: Building Solar Through a Pandemic and a Tsunami on a Pacific Island
Few Pacific energy projects have faced a tougher build. Construction ran through the COVID-19 pandemic, while Tonga’s borders were closed. Sunergise received one of the first entry exemptions for non-residents, which allowed the team to scale up and train the local workforce on site. Then, in January 2022, the Hunga Tonga–Hunga Ha’apai volcanic eruption and tsunami struck and cut Tonga’s communications for weeks. As soon as contact was restored, the teams from Sunergise, Clay Energy and Tonga Power returned to work and delivered the project through close coordination with local and regional partners.
Sunergise’s Solar Power Solution for Tonga and the Pacific people
Sunergise and Clay Energy designed and built three interconnected 2.3 MWp ground-mounted arrays in western Tongatapu, totalling 6.9 MWp. More than 17,000 Trina Solar panels feed 33 ABB inverters. Under the PPA, Tonga Power buys the solar electricity without funding the plant upfront, a model that makes utility-scale solar achievable for Pacific utilities. Marking a shift to renewable energy, the farm powers the up to 10,336 households and offsets 18% of Tongatapu’s diesel-powered generation. Up to 70% of the construction labour came from local Tongan civil, mechanical and electrical sub-contractors, so the skills built on this project stay in the Kingdom.
Project Highlight: Launched in the Presence of the King of Tonga and Community Leaders
In December 2022, the Prime Minister of the Kingdom of Tonga, Hon. Hu’akavameiliku, officially launched the solar farm at Fualu in the presence of their Majesties King Tupou VI and Queen Nanasipau’u.
