Norwegian certification body DNV GL has signed a contract with Huadong Engineering to provide technical advisory support on feasibility study for the first high-voltage direct current (HVDC) offshore wind substation in China.


Image: DNV GL to support Chinese offshore HVDC substation. Photo: Courtesy of DNV GL AS.

China is planning to expand its offshore wind power generating capacity. Presently, it has plans to deploy 5GW of offshore wind power by 2020. Last year, it installed nearly 1.2GW of offshore wind.

However, the country is facing a challenge in exploiting all the wind farm sites within 10km of shore. To boost capacity and further its 2020 offshore ambitions, the country plans to explore locations that are further offshore.

To this end, Huadong Engineering is planning to construct a 1.1GW offshore wind farm some 90km off the coast of Jiangsu Province in eastern China.

As per DNV GL, traditional submarine high-voltage alternating current (HVAC) cables are considered to be extremely inefficient for transmitting large amounts of electricity over such long distances. In contrast, high voltage direct current (HVDC) systems can be used for transmitting power over large distances under the sea with minimal losses.

DNV GL – Energy Offshore Wind APAC head Deng Pan said: “Compared to onshore HVDC technology, offshore wind HVDC technology has more unique specifications, as a combination of both offshore wind and HVDC technology need to be applied in limited space in order to satisfy safety and functional requirements.

“DNV GL is pleased to work with the customer on this HVDC milestone project to accelerate the development of the local offshore wind industry based on our extensive offshore wind experience.”

Hence, a major part of the new project will be the development of an offshore HVDC transmission system to export offshore power from the wind farm to mainland including offshore HVDC converter station, submarine cables and onshore HVDC converter station.

Under the contract, DNV G will provide technical trainings, advices and support on feasibility study on aspects of conceptual design and risk assessment.