China will invite public bidding for more offshore wind power projects in the next five years to reach an installed offshore wind-power capacity of 5 gigawatts by 2015, senior officials said on Monday.

China's offshore wind-power capacity may reach 5gW in 2015 and 30gW by 2020, Wang Minhao, vice-president of the Hydropower Planning Research Institute, said at an industry conference in Shanghai, citing local governments' preliminary development plans.

The institute, affiliated to the Ministry of Water Resources, is responsible for the planning and design of China's hydropower and wind power projects.

"Although such a target is yet to be officially approved by the central government, the nation will definitely invite public bidding for more offshore wind power projects in the next five years, following the first batch of four such huge projects established in eastern part of Jiangsu province," said Li Junfeng, deputy director-general of the Energy Research Institute affiliated to the National Development and Reform Commission.

He said that more projects would soon be rolled out in Jiangsu, Shandong, Zhejiang and Fujian provinces, and Shanghai municipality.

"Authorities would not wait until the completion of the first four projects for the start of new ones" in order to meet the 5gW target in 2015," he added.

"China has accelerated the construction of offshore wind power projects along the eastern coast since last year," said Wang Jun, director of the New Energy and Renewable Energy Department of China's National Energy Administration.

The move is to meet the huge needs of the nation's energy-hungry eastern cities.

"Meanwhile, that's given that transmission of on-land wind power from China's west to the east of the country is much less efficient," he added.

Four offshore wind power projects in Jiangsu province with a combined capacity of 1gW are currently under public bidding.

The four projects include two near-shore plants, each with installed capacity of 300 megawatts, and two built on tidal flats with a capacity of 200mW each, the National Energy Administration said earlier.

Public bidding for these projects started on May 18 and is expected to finish in September.

China has also finished construction of a pilot offshore wind power project at East China Sea Bridge near Shanghai, with an installed capacity of 100mW.

Investment in the project is 2.5 times that of an on-land project with the same capacity.

Wind power is considered one of the most economically viable renewable energies to help China realize its target of getting 15 percent of its energy mix from non-fossil energies by 2020.

China's wind power industry has seen over 100 percent year-on-year growth in the past four years.

The country's installed wind power capacity has reached 25gW, the second-largest in the world.

The nation's combined wind power capacity is expected to reach 150gW by 2020.