The Tonga prime minister, Lord Tu'ivakano, has laid the foundation for the country's 4th solar energy farm.
The latest, backed by the Japanese government, is being built at Vaini on the main island, Tongatapu.
It will cost an estimated 10 million US dollars and be a similar size to a solar farm built with New Zealand's help at Maama Mai.
Radio Tonga reports the minister of public enterprises, Fe'ao Vakata, says the Vaini farm can help cut costs and reduce reliance on diesel.
The Japanese ambassador to Tonga, Kazuchika Hamuro, says Japan wants to help Tonga ensure sustainable energy for all.