The China Three Gorges Corporation successfully installed the biggest single-unit floating wind energy generation platform in the world on the coast of Guangdong Province.
Located 40 nautical miles out to sea and at depths of more than 164 feet, the machine delivers 16 megawatts. It works under harsh conditions where a stable base is not possible.
The platform has a reported displacement of 24,100 tons, and its rotor diameter is an amazing 827 feet.
Pumping ballast water to fight offshore sway
The impact of winds on a turbine blade with 886 feet of tip height generates a considerable overturning force.
High winds hitting the 827-foot-long rotor lead to physical forces working to tilt the three-column semi-submersible structure from its upright position.
A ballast system mitigates this hazardous pitch-and-roll action.
Using automation, the ballast system transfers seawater between tanks located within the three columns of the structure to create counterweights for the forces generated by wind and waves.
This active balancing helps the structure withstand wind without putting undue stress on the mechanical parts.
Maintaining balance helps reduce operational stress on the main shaft and gearbox.
Why synthetic mooring lines absorb wave shock
Anchor chains alone cannot handle 65-foot typhoon waves.
Traditional steel cables carry destructive peak load spikes straight to the seabed anchors when huge waves lift a huge semi-submersible platform.
Engineers traded heavy steel cables for high-strength synthetic fiber cables made from polyester.
The flexible synthetic lines have a tensile strength rating of up to 1,300 tons, and under extreme loads, they stretch to absorb wave energy via their elasticity.
Nine suction anchors planted into the seabed keep the whole mooring system firmly in place.
Such an arrangement limits lateral movement and enables the floating vessel to weather 160 mph winds without breaking its moorings on the seabed.
Transmitting power through a flexing seabed cable
Transmission of electricity to land from such a station involves the use of a special kind of dynamic cable.
As the floating foundation is in constant movement with surface waves, normal subsea cables would easily become fatigued and break down.
A 66-kilovolt dynamic cable was used in the construction of a lazy-S waveform configuration.
The lazy-S underwater design gives slack for the cable to move and flex with the changing positions of the platform.
This cable feeds green energy straight to the mainland grid system.
It is projected to produce 44.65 million kilowatt-hours of electricity per year, which would be enough to supply electricity to more than 24,000 homes with three people annually.
Why scaling single turbines lowers floating costs
Offshore deepwater wind farms continue to be much costlier than on-fixed-bed installations.
The implementation of sophisticated floating structures, anchoring systems, and dynamic cables is costly and hinders commercialization.
Use of large-scale 16 MW turbines makes such projects more economically viable.
Distributing the cost of mooring and construction for one very large turbine reduces the cost per kilowatt generated by more than 50 percent compared to early designs.
Bigger turbines reduce the overall sea space required per MWh, as reported by the China Three Gorges Corporation.
With one single blade sweeping an area of about seven football pitches, larger turbines harness much more wind energy without increasing the cost of mooring equipment.
What deep-water engineering changes for global energy
Near-shore shallow waters have become more and more congested with fixed-bottom wind farms.
Harnessing wind energy beyond 164 feet of water depth can provide energy resources two to three times more powerful than those of coastal areas.
Demonstrating single-unit floater design serves as a prototype for utility-scale offshore deployment.
Demonstrating active ballast control and synthetic mooring systems on this unit aims to gather operational data and support the path toward future commercial projects in deep ocean water.
Floating wind projects have evolved from the experimentation phase to standardization in commercial applications.
Deepwater wind farms are becoming major contributors to global clean energy growth by proving their survivability in super typhoons, and Goldwind is moving with the times.
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