Profiling Corrosion Rates for Offshore Wind Turbines with Depth in the North Sea

Abstract

Corrosion in the marine environment is a complex and expensive form of damage. It is commonly studied by the deployment of coupons that reflect the marine corrosion a structure will experience, thus allowing design and maintenance prevention strategies to be developed accordingly. This study stems from the lack of information in the literature regarding the profiling of corrosion with respect to marine depth in the North Sea where important wind farm developments have been undertaken. To address such issue a field experiment has been designed and carried out in the vicinity of the Westermost Rough Windfarm in the North Sea. The field experiment consists of deploying steel S355 coupons below the tidal area and capturing the effects of corrosion, the mass loss from which the corrosion rate is derived and the chemical products that makes up the rust with water depth. The study involves proper planning and logistics to ensure that the field experiment survives the rough conditions of the North Sea for a duration of 111 days. A high corrosion rate of 0.83 mm/year has been observed in this experiment. This paper goes into the details of the deployment blueprint employed and the analyses of the coupons to provide a conclusive observation and modelling of corrosion with respect to water depth under free or open sea water corrosion condition.

Ultrasound-Based Smart Corrosion Monitoring System for Offshore Wind Turbines

“…Different reasons can be identified behind the growth of corrosion process in an offshore structure, such as temperature, salinity, pH, and coating damage due to tidal fluctuations, dissolved oxygen, variable cyclic load due to wave and wind impact, etc. [17].…”

Review of corrosion monitoring and prognostics in offshore wind turbine structures: Current status and feasible approaches

“…In both atmospheric and immersed conditions, carbon steels mainly corrode uniformly, with a homogeneously distributed metal loss over the surface. However, localized corrosion may also develop on a surface initially corroding uniformly (Khodabux et al, 2020), explained due to effects from biological organisms in the sea water and the built-up of corrosion products. Non-uniform corrosion mechanisms happen when the electrochemical cell is distributed in an abnormal way over the surface of the metal, such that anodic and cathodic sites differ in size, resulting in an accelerated localized loss of metal and the formation of cavities and holes.…”

Corrosion in marine and offshore steel structures: Classification and overview

“…Although the individual impacts of these factors on corrosion are well understood, the combined influence of these factors together are complicated and unknown. According to the work done by (Khodabux et al, 2020), some examples about corrosion rates from different locations are shown in Table 2.…”