Modelling water replenishment and anti-corrosion systems in offshore wind turbines

Published: 13 March 2018

Deltares developed a new tool to model water replenishment and anti-corrosion systems inside offshore wind turbines. By linking realistic metocean conditions with water quality processes Deltares can help with the optimisation of the number, positioning and size of water replenishment holes in monopiles.

These replenishment holes are needed to prevent acidification of stagnant water, which can cause damage to sensitive cables and other fitting inside the monopile. This acidification is caused by the chemical reactions of the Impressed Current Cathodic Protection (ICCP) used to prevent corrosion of monopiles in offshore wind farms. More and more ICCP systems are being used in offshore wind to prevent corrosion. In recent years there has been an increased awareness of the risk of corrosion inside monopiles. This awareness is mainly stimulated by decisions and decommissioning of existing foundations, where more corrosion than expected was observed. This has led to the installation of anti corrosion systems.

Physical model tests of water replenishment inside a monopile under wave and current conditions

Coupling of hydrodynamic model with water quality model

The newly developed tool couples a hydrodynamic model with the water quality model DELWAQ. It allows Deltares to determine the pressures and wave action inside the monopile, the effect of marine growth, flow velocities through replenishment holes and pH levels in the monopile. This information can then be used to optimise the positioning and the size of replenishment holes. The hydrodynamic flow model has been validated with physical model experiments performed in our wave and current physical model facility, the Atlantic Basin.

Dr. Bo Terp Paulsen, Senior consultant in the offshore department at Deltares, will be giving a presentation on 14 March on this topic at the 4th International Conference Corrosion Protection for Offshore Wind.