The Kingdom of Tonga is an archipelago in the South Pacific. The islanders’ electricity is supplied by diesel generators, which are an expensive energy source. With more than 1,500 hours of sunshine annually, Tonga has an additional source of energy: the sun. The Tongan island chain of Vava’u is now making use of this energy source.

A photovoltaic diesel hybrid system went into operation in Vava’u in November 2013. The project was funded through a grant from the government of the United Arab Emirates, managed by Masdar and implemented by Ingenero. The system is designed to reduce diesel fuel consumption and associated costs. The 500 kW hybrid PV farm, comprising 1,680 PV modules and 21 SMA Sunny Tripower inverters, was fully integrated into the existing diesel network and meets almost 70 percent of Vava’u’s electricity demand at noon. Batteries store part of the energy generated during the day and discharge it during the evening peak.

The SMA Fuel Save Controller controls the PV-diesel hybrid system. Working with the SMA inverters, it coordinates PV feed-in according to current electricity demand. The Fuel Save solution supports a secure energy supply by coordinating the PV inverters and diesel generators based on demand.