Third law of repetitive electric Penrose process

Abstract: Recently, Ruffini et al. [Phys. Rev. Lett. 134 (2025) 8, 081403] pointed out that the repetitive Penrose process cannot drain the entire extractable energy of a Kerr black hole. In this Letter, we further point out that the charge of a Reissner-Nordstr\"{o}m black hole cannot drop down to exactly zero via the repetitive electric Penrose process that is terminated after a finite number of iterative steps, indicating a thermodynamical third-law analog for the repetitive electric Penrose process.