Cathodic Protection in Offshore Wind: Impressed Current vs Galvanic Anodes

The experience matured in the oil&gas industry concerning corrosion engineering has seen offshore structures, as for example jackets, protected from corrosion by aluminium alloy anodes. Impressed current cathodic protection systems are also frequently used, although they are more popular for retrofitting purposes rather than for application on new structures. The development of renewable energy, and in particular of offshore windfarms, is leading to new questions concerning the potential environment effects of cathodic protection: on one side, galvanic anodes imply the release of metallic oxides in seawater which affect both marine flora and fauna, and on the other hand impressed current implies evolution of chlorine, which can have a biocide effect. A comparative study between galvanic anodes and impressed current cathodic protection system is here presented, both in terms of advantages/disadvantages brought to the protection of the structure and in terms of impact on the environment.