Solar Desalination in Tonga: Clean Water Solution for Climate-Resilient Island Communities

Water Scarcity and Drought in Pacific Island Nations

Tonga, like many Pacific Island nations, faces increasing challenges due to drought and limited freshwater availability. Climate-resilient solutions are urgently needed.

Project Snapshot

Location: Tonga
Partners: Australian National University (ANU), Institute for Climate, Energy and Disaster Solutions (ICEDS), Tongan Ministry of Agriculture, Food and Forests (MAFF), Sustainable Water Systems, Solar Water Solutions, Local communities
Installation Date: 2025
Technology: SolarRO reverse osmosis desalination unit for off-grid water treatment

Solar desalination for climate-resilient island communities

In response to increasing water scarcity and climate vulnerability in the Pacific, we succesfully installed a solar-powered reverse osmosis system in Tonga as part of a pilot project under the SciTech4Climate initiative. This marks a critical step in deploying sustainable, low-emission technologies to support water and food security in remote island communities.

The project demonstrates how solar desalination can be applied to support clean water production in climate-vulnerable island communities. By combining solar energy with reverse osmosis technology, the solution supports the project’s goal of strengthening water and food security in remote locations.

Supporting water and food security with solar desalination

The pilot project aims to support water and food security in Tonga while evaluating the potential of solar desalination in drought-prone and remote communities. The project goals are to:

• Provide a clean, reliable source of potable water powered entirely by solar energy
• Evaluate the feasibility of solar desalination for agricultural use, especially in drought-prone rural areas
• Build local technical capacity through community involvement and training
• Contribute to long-term climate adaptation strategies in the region

Off-grid solar reverse osmosis installation in Tonga

The installation was carried out in collaboration with local contractors, ANU researchers, and ministry staff. The containerized SolarRO unit was paired with a dedicated solar array and water storage infrastructure, enabling fully off-grid operation. The solar desalination system achieves up to 99% salt rejection, making seawater or brackish sources safe for irrigation and human use. The installation in Tonga features our containerized SW18 model, a compact and energy-efficient solar reverse osmosis unit. Designed for remote and off-grid use, the SW18 unit’s energy consumption is 4,9 kWh, and it requires minimal maintenance. This solution is powered entirely by solar energy — with no need for fuel or grid connection.

Building Water Resilience in Climate-Vulnerable Communities

While operational data is still being collected, early feedback from stakeholders has been positive. Local teams have been trained in operation and maintenance, and crop trials for salt-sensitive species such as taro and yam are underway.

The project is already demonstrating the potential for sustainable desalination to enhance water resilience in vulnerable island communities. As a water system for remote communities, the project brings together solar-powered desalination, local technical capacity, and the ongoing evaluation of water use for both potable water and agriculture.

Solar-powered desalination at a glance

The Tonga project demonstrates how solar desalination can combine reverse osmosis technology with solar energy for clean water production in remote island communities. The containerized SW18 system operates fully off-grid, using a dedicated solar array and water storage infrastructure.

As an island desalination system, the solution is designed for remote and off-grid use and is powered entirely by solar energy. The project also evaluates the feasibility of solar desalination for agricultural use in drought-prone rural areas, while providing a clean and reliable source of potable water.

Together, solar reverse osmosis and off-grid desalination offer an approach to supporting water and food security in climate-vulnerable island communities.

Looking for solar desalination for your community?

Looking for a reliable solar desalination system for an island or remote community? Our modular, solar-powered reverse osmosis systems are designed for remote and off-grid applications.

Contact Solar Water Solutions to discuss your clean water needs and find a suitable desalination solution for your community.

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