Economic efficiency in using the solar panels as the DC sources for the impressed current cathodic protection of offshore structures was compared with the sacrificial anode cathodic protection. The calculation was based on the example of a sheet pile wall with a surface area of 2000 m2 protected by various methods of cathodic protection: the impressed current cathodic protection powered by a rectifier device, by solar panels with batteries, by solar panels without batteries and sacrificial anode cathodic protection. The results showed that the cost of impressed current cathodic protection powered by solar panels without batteries is the lowest after 10 years of operation. Cathodic protection powered only by solar panels without batteries is the most beneficial in cold climates when battery life is reduced, and for facilities that are remote from centralized power sources, where the power supplying cost to the protected structure is difficult to estimate due to specific situations.

The operability of a cathodic protection device for marine structures powered only by a solar panel without the use of other direct current sources is experimentally studied. A quantitative assessment of the corrosion protection ability of such a device is carried out at four current densities of cathodic protection for low-alloy metals. To determine the possibility of using such protection of objects that may have corrosion products on their surface in comparison with objects that immediately after immersion in sea water are protected by cathodic protection, four test samples have a clean surface before testing, and the other four have corrosion products of low-alloy steel. It is shown that the protective effect of pure samples reaches 64% at a current density of 0,387 Amperes per square meter, and the protective effect of samples with corrosion products reaches 70% and 95% at protection current densities of 0,203 and 0,387 Amperes per square meter respectively. In order to ensure maximum protection of steels, cathodic current densities of more than 0,2 Amperes per square meter are required, which are easily achieved by using solar panels. The protective ability of such modes to protect the marine structures from corrosion is achieved by the formation of coatings of calcium carbonate and magnesium hydroxide in the daytime, which are able to protect objects in the night, currentless period of time. The using possibility of cathodic protection for protecting metals in seawater using solar panels when other direct current sources are not used is proved. Obviously, it is advisable to use such devices to protect offshore structures in the areas located away from stationary sources of electricity and human resources, while saving significant material resources.

The operability of the device for cathodic protection of metals in natural seawater using the solar panel as the only direct current source was experimentally studied. It was shown that the cathode device, powered only by a solar battery, allows cathodic protection of marine structures with a degree of protection of up to 86% without the use of additional energy sources. Protection is achieved by the formation of calcareous coatings in the daytime, which provide protection in the nighttime, when the cathode current is absent.

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