China erects a 25,000-ton colossus in the ocean to break wind energy records, take turbines more than 100 km offshore, and release 6 billion kWh per year for one of the most industrialized regions in the country.

A colossal structure installed offshore shows how China is trying to overcome technical barriers of offshore wind energy, bringing renewable generation to more distant, complex, and strategic areas of the ocean.

China has increased its stake in offshore wind energy with the construction of the Hai Feng Zhi Xin, an offshore converter station weighing about 25,000 tons designed to bring electricity from wind farms far from the coast to the land grid.

The structure departed from Nantong, in Jiangsu province, and will be installed in the waters near Yangjiang, in Guangdong, where it is expected to serve the Qingzhou V and Qingzhou VII projects, linked to the China Three Gorges Corporation.

The equipment was built by the state-owned Shanghai Zhenhua Heavy Industries Co., Ltd., known as ZPMC.

In a statement, the company describes the platform as the largest offshore converter station in the world.

The structure is 85.5 meters long, 82.5 meters wide, and 44 meters high, dimensions close to the area of a football field and the height of a multi-story building.

More than its physical size, the platform’s function explains the technical relevance of the project.

The station was designed to gather electricity produced by offshore wind turbines, increase the voltage, and convert alternating current to direct current.

This process allows energy to be transmitted over long distances in submarine cables with lower losses, according to ZPMC and reports from the Chinese state press.

Offshore wind energy faces the challenge of distance

The expansion of offshore wind energy encounters a physical limitation known to the electric sector.

The turbines produce electricity in alternating current, a model widely used in conventional grids.

In very long submarine cables, however, transmission in alternating current tends to cause greater losses and requires more complex technical solutions.

For this reason, many wind farms have historically been installed in areas relatively close to the coast.

The proximity reduces the cable distance and simplifies the connection to the grid.

At the same time, it limits access to maritime regions where winds are usually more constant and suitable for large-scale generation.

The proposal of Hai Feng Zhi Xin is to act as an electrical substation in the ocean.

The platform receives the energy produced by the turbines, converts the current, and prepares the electricity to follow to the coast through submarine direct current lines.

In the technical evaluation released by ZPMC, this model helps to enable projects located more than 100 kilometers from the coast.

The station will have a unit capacity of 2,000 megawatts and is expected to collect energy from 163 offshore wind turbines.

The system uses flexible transmission in 500-kilovolt direct current and, according to the company responsible for the project, also involves the application of 525-kilovolt submarine cables in direct current.

Direct current allows energy to be carried by submarine cables

The difference between alternating current and direct current helps to understand the role of the platform.

In alternating current, the electrical flow changes direction in cycles.

In direct current, electricity flows in a single direction, a characteristic that can reduce losses in long-distance transmissions, especially in submarine connections.

This technical choice directly affects the geography of wind farms.

Without an efficient transmission solution, plants far from the coast can become economically less attractive.

With offshore conversion, electricity produced in more distant areas can be sent to the land network with greater operational stability.

ZPMC states that the station will allow the utilization of wind resources in more distant waters, where wind conditions are considered by the sector to be more favorable for large-scale projects.

When the system is completed, the forecast released by the company is that the structure will contribute to the annual supply of about 6 billion kilowatt-hours of renewable electricity.

The platform does not generate energy on its own.

Its role is to mediate the electricity produced by the turbines and allow it to reach the continent in conditions suitable for integration into the network.

In practice, it functions as a link between the turbines installed offshore and the consumer centers located on land.

Offshore platform was designed to operate without a fixed crew

The construction of the station followed a modular model.

Instead of assembling the structure directly at sea, ZPMC carried out the manufacturing, equipment integration, and part of the installation stages on land.

After that, the platform was transported whole by a semi-submersible vessel to the planned installation site.

Yan Bing, senior specialist at ZPMC, stated in the company’s announcement that the project adopted the model of “onshore assembly, transportation as a single unit, and installation by floating”.

The technique, known as float-over, reduces some of the interventions made in the offshore environment but requires coordination between engineering, maritime transport, and ocean conditions.

Installation at sea requires fitting the superstructure onto the previously prepared base.

According to reports from Chinese media, the procedure demands high precision during the operation, as ocean currents, waves, and wind interfere with the positioning of the structure.

The stage is considered one of the most sensitive phases of projects of this type.

Once positioned, the station was planned to operate without permanent human presence.

Remote monitoring systems and intelligent maintenance are expected to oversee the electrical equipment, ventilation, safety mechanisms, and fire-fighting systems.

This automation reduces the need for frequent trips to the platform and meets the operational requirements in a maritime environment.

Salinity, humidity, and corrosion are among the factors that condition the project.

Therefore, internal components need to receive specific protection and continuous control systems.

In offshore platforms, maintenance failures can have high costs, both due to the distance from the coast and the need for specialized vessels.

China expands offshore wind energy projects

The advancement of Hai Feng Zhi Xin occurs at a time of expansion of China’s renewable capacity.

China’s 15th Five-Year Plan, covering the period from 2026 to 2030, foresees that the installed capacity of offshore wind energy will reach 100 gigawatts by 2030, according to an analysis by Carbon Brief based on the document.

Guangdong, the destination of the energy associated with the Qingzhou V and Qingzhou VII projects, is one of China’s most industrialized provinces.

The region concentrates manufacturing activities, urban centers, and high electricity consumption.

In this context, the installation of offshore wind farms is part of China’s strategy to expand non-fossil sources and diversify the electricity supply.

The search for more distant areas also stems from the competition for spaces near the coast.

Shallow waters and coastal stretches facilitate the installation of turbines, but have limited availability and competing uses, such as navigation, fishing, port infrastructure, and environmental preservation.

Moving to more remote regions requires larger structures, longer cables, and more sophisticated transmission technologies.

The Yangjiang project brings together some of these challenges in a single chain.

In addition to the turbines, heavy transport ships, high-voltage submarine cables, converter platforms, digital control systems, and specialized offshore installation teams are needed.

The result is an energy infrastructure that relies on both wind generation and naval and electrical engineering.

Energy transition depends on offshore infrastructure

Hai Feng Zhi Xin shows how offshore wind energy has come to depend on solutions that go beyond increasing the size of turbines.

Transmission, grid integration, and remote operation have become central parts of offshore expansion.

Without these elements, more distant parks remain limited by cost, maintenance, and electrical losses.

According to ZPMC, the platform will be connected to the Qingzhou V and Qingzhou VII parks and is expected to operate as a conversion and dispatch point for the renewable energy produced at sea.

The company also associates the project with the attempt to form a technical model for future installations in distant maritime areas.

This expansion, however, does not eliminate the environmental and regulatory challenges associated with large offshore structures.

Projects of this magnitude require studies on marine impact, cable routes, interference with local economic activities, and long-term maintenance.

These points do not appear as secondary details: they influence cost, licensing, and public acceptance.

In the Chinese case, the scale of the project draws attention for the combination of heavy engineering, energy planning, and the use of direct current transmission.

The 100-kilometer barrier ceases to be just a matter of distance and comes to depend on the ability to integrate generation, cables, electrical conversion, and remote operation into a single system.

For the field of science and technology, the platform serves as an example of how the energy transition also depends on infrastructure invisible to the consumer.

The electricity that reaches the outlet starts at the turbines but only becomes useful on a large scale when it can cross the sea, enter the grid, and meet demand with stability.