Electric vehicle charging stations will be built on an artificial island off the world's longest sea bridge, authorities said Saturday.

The main structure of the sea bridge linking Hong Kong, Zhuhai and Macao was completed Friday.

Representatives with the Guangdong branch of China Southern Power Grid said that the 550 stations, with an investment of 90 million yuan (13 million U.S. dollars), would be completed and put to use at the end of 2017. They will help "facilitate green development," according to the company.

The stations can be used to charge different kinds of electric vehicles, such as public buses, long-distance coaches, travel buses, shuttle buses and electric taxis. There will be 429 DC charging stations and 121 AC charging stations.

It took seven years to build the Y-shaped bridge, which will be open at the end of the year. It will slash travel time between Hong Kong and Zhuhai from three hours to just 30 minutes, further integrating cities in the Pearl River Delta.