In this study, we analyzed the application of photovoltaic solar energy as a source of cathodic protection in metallic structures foundations on transmission lines towers. As preliminary studies concerning the need for cathodic protection of the structure, we have measured the resistivity of the soil, the pH and the natural corrosion potential. After the verification of the need for protection against corrosion, the cathodic protection system (CPS) was designed calculating the current to be injected, the PV system and a monitoring system. For analyzing the efficacy of the CPS, a comparison was made between the measurements done in two towers very close to each other, one with a CPS and the other acting as a witness. By comparing the loss in masses of the carbon steel coupons installed around the base of both towers and the measurements of the potentials reached due to the injected current, the efficacy of this system was experimentally demonstrated. In the protected tower, the rate of mass loss experienced a decrease by a factor equal to 2.5. Finally, the economical analysis using the LCC, showed that the usage of CPS has a significant and clear advantage regarding traditional methods.