Vietnam inaugurated an undersea cable system to transmit power to its largest island in the southern region on Thursday after nearly three months of construction.

Building work began last year on November 17 on the 55.8-km submarine 110kV cable system, dubbed the longest of its kind in Southeast Asia, which delivers electricity from the Mekong Delta province of Kien Giang’s inland Ha Tien Town to Phu Quoc Island located tens of kilometers offshore.    

The inauguration of the system, worth VND2.33 trillion (US$111 million), formally connected Phu Quoc to the national power grid, although electricity already started being supplied to the island on February 2.

The cable will help islanders save more than VND200 billion ($9.5 million) a year as they now have to pay only slightly over VND1,700 per kWh on average, instead of VND5,060, as before.     

Phu Quoc residents used to rely on diesel generators to light up their homes and power their TV sets.

The construction was funded by a loan from the World Bank and supplemented with Vietnam’s own budget.

Phu Quoc Island, Vietnam’s largest island, is 120km off Kien Giang’s capital Rach Gia City and 45km off Ha Tien.

It is a district under the administration of the province, with a total area of 589 square kilometers and over 100,000 residents.