How Controlled-Potential Cathodic Protection Systems for Subsea Structures Can Reduce Cost and Improve Safety

Abstract Traditional subsea cathodic protection often overprotects steel structures by driving potentials far more negative than required, increasing current demand, accelerating sacrificial alloy consumption, inflating installation mass, and critically promoting hydrogen evolution. The excess hydrogen flux into high-strength steels raises hydrogen embrittlement risk. This work proposes a controlled-potential anode architecture featuring compact, distributed anodes engineered to maintain a narrow potential window of -0.80 to -0.90 V vs. Ag/AgCl/seawater. Controlled-potential anodes meet protection requirements while minimizing driving force for hydrogen generation. Unlike alloy-activated low-voltage galvanic anodes whose performance degrades due to film formation or fouling, controlled-potential anodes remain electrochemically stable over time. We present theoretical models and literature-backed analysis on expected reductions in current and mass requirements, improvements in safety through reduced hydrogen charging, and enhancements in logistics and lifecycle cost. Laboratory testing and field observations demonstrate the approach's viability. Practical guidelines for integrating controlled-potential anodes into new and retrofit designs, compatible with current frameworks, are discussed.