A 500 kilovolt submarine electricity cable link connecting the power system of South China's Hainan Province with the China Southern Power Grid through the Qiongzhou Straits will be finished and put into use by the first half of 2009.

Xinhua, the official state news agency, reported on Tuesday that the cable link extends from the Gangcheng transformer station in Guangdong Province's Zhanjiang City to the Fushan transformer station in Hainan's Chengmai County.

The cable link, consisting of 34.7 kilometers of submarine power cable and 144 kilometers of trolley wire, has a designed transmission capacity of 600,000 kilowatts.

The project, which began in early 2007, cost 2.1 billion yuan (271 million US dollars), and will be the longest power grid connection project in the world upon completion. It will serve to improve the Hainan power grid's safety and efficiency.

China Southern Power Grid incorporated the Hainan power grid in November 2004, and has since invested 4 billion yuan to upgrade the province's power transmission systems.

China Southern Power Grid, a state-owned power grid firm, covers the southern provinces of Guangdong, Yunnan, Guizhou and Hainan, and the Guangxi Zhuang Autonomous Region, providing electricity to 230 million people.