The Importance of Asset Integrity
Wind power has convinced individuals and governments that there is a promising future for renewable energy – including that most practical state of Texas, which leads the US in wind production.
But if it takes 10-15 years, perhaps more, for an investment in a wind turbine to pay for itself, owners want to make sure they protect their assets for the long haul.
This is especially true in offshore wind farms, where the wind is generally better, but the environment more corrosive.
So, what do offshore wind farm owners and operators need to keep in mind to ensure a long lifespan and low maintenance cost for their assets?
Initial Surface Preparation and Coating
The principle exterior parts of wind turbines, towers, blades, nacelle, etc., are shop coated prior to being installed onsite in the water. While the blades themselves are typically made of some composite material such as glass or carbon fiber, the other main structural components are built from steel. While the blades face impact wearing from airborne materials such as dust, heavy rain, and unlucky birds, the main problem for steel is of course corrosion.
In selecting the right coating system and surface preparation protocol, specifiers should consult the relevant industry standards, like ISO 19244 or NORSOK M-501. As Michael MeLampy of PPG discusses in a recent JPCL Article, offshore wind specifiers can learn from the decades of experience, testing, and standard setting by other major projects, such offshore Oil & Gas and infrastructure.
As with any steel surface preparation job, ensuring a clean, rust-free, salt-free surface with adequate profile is key for protecting the life of the coating. For contractors and specifiers encountering rust back or chloride and other salt contamination, we recommend the use of HoldTight 102.
Maintenance and Repair
For high durability coatings, according to ISO 12944, if the coating is properly applied, maintenance recoating should not be necessary for 15-25 years. When it is, surface chlorides and other soluble salts are likely to be a big challenge. This salt contamination need to be removed before recoating.
Even before the first maintenance is done years after the turbine is installed, there may be touch up work to be done as damage to the coating can often occur during transportation and construction. These spots need to be properly repaired, and are also likely to be highly exposed to atmospheric salts in their environments.
For testing on the use of HoldTight 102 in similar environments, for offshore atmospheric maintenance coatings with water jetting, check out this case study.