China's first offshore HVDC line planned

CHINA: Power China Huadong Engineering Corporation is planning a 1.1GW project that will include the country's first high-voltage direct current (HVDC) transmission system for offshore wind.

China currently has 2,788MW of installed offshore capacity, according to Windpower Intelligence

HVDC technology will enable projects to be located further offshore — such as Huadong’s site approximately 90km from the coast of Jiangsu province in eastern China.

Traditional submarine high-voltage alternating current (HVAC) cables are less efficient at transporting large amounts of electricity over long distances.

In contrast, HVDC systems allow more power to be transmitted over large distances under the sea with minimal losses.

China has the most installed wind capacity in the world. It currently has 173.7GW online, according to Windpower Intelligence, the research and data division of Windpower Monthly, of which 2,788MW is offshore. It plans to have 5GW installed offshore by 2020.

However, according to DNV GL, the certification body that is providing technical advisory support on feasibility studies for Huadong’s HVDC line, China faces challenges to reach the 2020 target. 

DNV GL said the country would need to explore locations further offshore that can only be connected by HVDC technology, as nearer-to-shore sites, traditionally served by HVAC connections, have already been exploited.