The Kingdom of Tonga is a Polynesian country with a group of more than 170 islands spread over an area of the South Pacific. The total surface area is about 750 km2 scattered over 700,000 square kilometres of the southern Pacific Ocean. The sovereign state has a population of 108,020 of whom 70% reside on the main island of Tongatapu. Tonga is the second most climate vulnerable country in the world.

Tonga’s economy is dominated by subsistence agriculture, and therefore relies heavily on weather conditions and world commodity prices. Tonga’s economy also relies on remittances from the Tongan population living and working overseas.

Tonga is highly dependent on imported fuels to meet its overall energy requirements. Tonga's total fuel imports account for about 25% of all imports and about 10% of GDP. Apart from diesel, the most attractive electricity generation technologies in Tonga are solar, wind and to a lesser extent, biomass. Solar energy resources have a high potential in Tonga, particularly towards the north, where satellite measurements indicate average insolations of up to 5.8 kWh/m2/day.

The main source for lighting is electricity supplied through the national grid which is powered by the government-owned Tonga Power Ltd (TPL) which generates, distributes and sells electricity to four of Tonga’s islands: Tongatapu, Vava’u, Ha’api and Eua. As 92% of the electricity on the TPL grid is supplied from diesel generation, the price of diesel fuel is the major component of the electricity tariff. The total generation (diesel plus renewable) in all four islands groups for the year ending June 2017 was about 66.5GWh. The total renewable energy generation for 2016/17 was 4,823MWh, which had increased by 2.0% compared to 2015/16 where it was 4,730MWh.

In 2009, the Government of Tonga approved a goal of 50% of electricity to be generated from renewable energy sources by 2020 and an additional target in its NDC to have 70% of electricity generated from renewable sources by 2030. Under Tonga Energy Road Map (TERM) and with TPL direct operational input, five major solar plants were constructed. Furthermore, TPL owns 65kW roof-top micro solar capacity with 510kW of third-party micro solar capacity owned by private customers.