WATER ELECTROLYSIS SYSTEM AND METHOD FOR OPERATING WATER ELECTROLYSIS SYSTEM

This water electrolysis system is provided with: a water electrolyzer; a negative electrode-side gas flow path through which a negative electrode-side gas flows; a monitoring device that monitors at least one among the hydrogen or oxygen concentration in the negative electrode-side gas in the negative electrode-side gas flow path, and the amount of power supplied to the water electrolyzer; a hydrogen supply path provided such that hydrogen gas can be supplied to increase the hydrogen concentration of the negative electrode-side gas flowing through the negative electrode-side gas flow path; anda flow rate adjusting valve that adjusts the flow rate of the hydrogen gas supplied to the negative electrode-side gas from the hydrogen supply path. 水电解系统具备水电解槽、流通有阴极侧气体的阴极侧气体流路、监测阴极侧气体流路内阴极侧气体的氢浓度或氧浓度或者向水电解槽的电力供给量中至少任一方的监测装置、设置为能以提高阴极侧气体流路内流通的阴极侧气体的氢浓度的形式供给氢气的氢供给路、以及调节从氢供给路向阴极侧气体供给的氢气的流量的流量调节阀。