Corrosion Protection: 
Input of Metals 
On the one hand, the protection current 
prevents the corrosion of steel struc- 
tures. On the other hand, it dissolves 
the sacrificial anode, and thus leads 
to components, such as aluminium or 
zinc, entering the marine environment. 
The amount of sacrificial anodes needed 
for the lifetime of offshore wind farms 
(25 years) varies greatly depending 
on foundation type, coating and local 
environmental conditions. 
Galvanic anodes in the area of offshore 
wind energy typically consist of alumi- 
nium-zinc-indium alloys (approximately 
95% aluminium; 2.5 to 5.75% Zzinc; 
0.015 to 0.04% indium). The galvanic 
anodes can also contain harmful heavy 
metals in small quantities, such as cad- 
mium, lead and copper which might be 
released into the marine environment 
as well. 
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According to current knowledge, there 
are no field studies so far that investigate 
the metal situation around offshore 
wind farms. Therefore, it is currently not 
possible to assess, whether offshore 
installations contribute significantly to 
the metal input of the North Sea, nor is 
it possible to assess potential impacts 
on the marine environment in the future.