Electric utility E.ON (Essen, Germany) is now protecting all 60 steel foundations of the Arkona offshore wind park in the German Baltic Sea with a special anticorrosion coating, making it the first company to fully assemble the monopiles of an offshore wind park with environmentally friendly corrosion protection technology.
Arkona is a joint venture between E.ON and energy company Statoil (Stavanger, Norway).
During the 25-year operating period, the metal-dissolving corrosion process will be significantly reduced and deposits into the sea reduced by several hundred tons, the company explains.
The utility developed the thermal-sprayed aluminum (TSA) process for coating of the monopiles with engineering group Rambøll (Copenhagen, Denmark), in coordination with local authorities.
Those companies then contracted with nearby pipe manufacturer EEW Group (Erndtebrück, Germany) and corrosion protection company Krebs (Hamburg, Germany) to develop solutions to implement the process industrially at their locations in Rostock, Germany. To this end, existing coating halls were also expanded, and the world’s first fully automated coating line was developed.
“We will now analyze and further optimize the process in order to use it for future offshore wind projects,” says Sven Utermöhlen, chief operating officer of E.ON’s climate and renewables business.
During the coating process, a robot with two arc burners sprays a 350-μm thick layer of molten aluminum onto the foundations. The process is carried out under stringent safety and environmental protection standards and is largely dust-free, the company explains. The surface is then sealed with resin.
Until now, the TSA process has mainly been used as corrosion protection for smaller steel components under water or for larger components above water, such as offshore substations. But the process is now being applied for the first time on an industrial scale for the foundations of the Arkona turbines.
Because the process is automated, this alternative coating method can lead to significant cost savings compared with conventional corrosion protection, the company explains.
All 60 foundations with the TSA coating for the Arkona offshore wind farm have been produced. They have a maximum length of 81 m and a diameter of up to almost 8 m, making them sufficiently wide to allow a train to pass through.
The Arkona project is located 35 km northeast of the island of Rügen. The wind farm will have a capacity of 385 MW and will be able to supply up to 400,000 households with renewable energy from 2019 onwards. Compared with conventionally generated electricity, Arkona says it will save up to 1.2 million tons of carbon dioxide (CO2) each year. Overall, 60 6-MW turbines made by Siemens will be installed based on monopile foundations in water, with depths of between 23 m and 37 m.
Source: E.ON, www.eon.com.