China has completed the first-stage of the Jiuquan wind power base, the country's largest wind power project, local officials said at the ceremony to mark the completion Wednesday in northwest China.

More than 3,500 turbines have been erected with an installed capacity of 5.16 GW, said Wang Jianxin, director of the Jiuquan Development and Reform Commission.

At present, 1.15 GW of turbines are generating electricity into the power grid, he said.

Construction on the second stage, with an installed capacity of 7.55 GW, was officially begun Wednesday.

Seven 750-kilovolt substations and a 1,780-km-long high voltage transmission line link the Jiuquan base to China's major east-west grid through which wind power can reach China's energy-hungry east.

The 20-billion-yuan wind power base, located in the windy desert near Jiuquan City, Gansu Province, started construction in August 2009 and is expected to be completed in 2015.

"The Jiuquan wind power base, after being put into full operation, can reduce carbon dioxide emissions by 16 million tonnes annually," said Li Jianhua, Communist Party chief of Jiuquan.

China is seeking to use more clean energy to reduce carbon emissions to protect the environment, a program that is driving wind, solar and hydropower construction booms.

Apart from Jiuquan, the world's second-largest economy has planned to build another six ten-GW wind power bases. China's total wind power generation is estimated to soar to 281 billion kwh by 2020 from 26.9 billionkwh in 2009.