Why Standard Zinc Plating Fails in Offshore Wind Turbines?

Corrosion Risks in Offshore Wind Generation
As more renewable energy comes online around the globe, offshore wind turbines have become one of the fastest growing renewable energy sources. However, the marine atmosphere is among the harshest environments on Earth where a new wave of offshore wind turbines is being installed. The mix of high salt concentration in the air, high humidity and exposure to ultraviolet (UV) radiation makes an extreme environment to degrade metal. The most common way to do so is to damage the fasteners.
Data from the National Renewable Energy Laboratory (NREL) also shows that the corrosion maintenance portion of a wind farm's 20 year operational costs represents approximately 25% of the total. This is a critical mistake in the use of standard zinc-plated fasteners (screws).

Why do standard zinc-plated fasteners fail?
Zinc plating(electroplating) is a thin film of protection (usually 5-8 microns thick). While zinc is an effective protection in mild conditions, its thin zinc layer is rapidly consumed by exposure to chloride ions found in sea salt spray. With no zinc left, the steel underneath immediately starts to rust and the product of rusting is hydrogen which will embrittle the steel so that it has a lower load carrying capability.
Using stainless steel screws in contact with carbon steel (tower flange - carbon steel) creates a situation where corrosion of the carbon steel item will be accelerated because when carbon steel and stainless steel are connected in a steel tower, they will form a galvanic corrosion process. Therefore the less noble or carbon steel part will corrode faster, thus speeding up joint failure.

Here is the coating approach that is superior to all others and meets all performance requirements: 

    Hot Dip Galvanized Steel (HDGS) fasteners are engineered to provide corrosion protection by means of a metallurgical bond between the fastener material and the coating. The resulting coating thickness ranges from 50-100 microns, depending upon the application, which provides barrier protection from both mechanical abrasio

    ASTM F1941:​ Standard Specification for Zinc Coating on Iron and Steel Hardware.

    EN 13889:​ Test methods for hot-dip galvanized coatings.

Conclusion

Specifying fasteners for offshore wind applications is not about finding the cheapest option; it is about calculating the lifecycle cost. By investing in fasteners with proven anti-corrosion technology—backed by material certifications and third-party test data—project managers can drastically reduce downtime and secure the structural integrity of wind turbines for decades.

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