Provided is a method of controlling a load of a water electrolysis stack in which a plurality of water electrolysis cells including an anode disposed on one side and a cathode disposed on the other side with a solid polyelectrolyte film interposed are stacked and housed. The method includes determining an appropriate load based on a condition of an inside of the water electrolysis stack obtained from at least one of a temperature of the inside of the water electrolysis stack, an electrical resistance, or a water flow rate, and changing application of the load on the water electrolysis stack such that the load is the appropriate load.

A modular solid oxide electrolyzer cell (SOEC) system including a stack of electrolyzer cells configured to receive steam in combination with hydrogen, and a steam recycle outlet configured to recycle a portion of the steam.

A modular solid oxide electrolyzer cell (SOEC) system including a stack of electrolyzer cells configured to receive steam in combination with hydrogen, and a steam recycle outlet configured to recycle a portion of the steam.

Systems and methods are provided for operating an electrolyzer. The systems and methods perform operations comprising obtaining a plurality of impedance measurements of the plurality of electrolytic cells at a plurality of frequencies; tracking changes to the plurality of impedance measurements of the plurality of electrolytic cells over a time period; and generating, based on the changes to the plurality of impedance measurements, a model representing operating conditions of the electrolytic cells on an individual electrolytic cell basis.

Systems and methods are provided for operating an electrolyzer. The systems and methods perform operations comprising obtaining a plurality of impedance measurements of the plurality of electrolytic cells at a plurality of frequencies; tracking changes to the plurality of impedance measurements of the plurality of electrolytic cells over a time period; and generating, based on the changes to the plurality of impedance measurements, a model representing operating conditions of the electrolytic cells on an individual electrolytic cell basis.

A carbon dioxide electrolytic device according to an embodiment includes: an electrolysis cell including a reduction electrode, an oxidation electrode, a gas flow path supplying gas containing CO.sub.2 to the reduction electrode, a liquid flow path supplying an electrolytic solution containing water to the oxidation electrode, and a diaphragm separating the reduction electrode from the oxidation electrode; a first supply path connected to the gas flow path; a first discharge path connected to the gas flow path; a first moisture content detecting unit installed in the first discharge path to detect a moisture content in the gas flowing in the first discharge path; a moisture content adjusting unit configured to adjust a moisture content supplied to the reduction electrode; and a control unit configured to control the moisture content adjusting unit based on a detection signal of the first moisture content detecting unit.

A controller stops flow of posolyte through a positive electrode chamber of a flow cell to trap the posolyte within the positive electrode chamber and hydraulically isolate the flow cell without stopping flow of negolyte through a negative electrode chamber of the flow cell, discharges the flow cell until hydrogen gas is evolved at a reactive surface of the positive electrode chamber while the posolyte is trapped within the positive electrode chamber, and subsequently discontinues the discharge and restarts the flow of the posolyte through the positive electrode chamber.

A method of operating a solid oxide electrolysis cell (SOEC) system at partial load, where the SOEC system includes a plurality of branches electrically connected in parallel, and each branch includes at least one SOEC stack. The method includes determining a thermally neutral target voltage below which operation is endothermic and above which operation is exothermic; and executing pulse width modulation current control by cycling an ON phase and an OFF phase for each branch such that the SOEC system operates at an average operating power equal to a chosen percentage of the operating power at the thermally neutral target voltage. In the ON phase, all of the SOEC stacks in a branch operate at the thermally neutral target voltage, and in the OFF phase, all of the SOEC stacks in the branch operate at 0% power. Each branch is configured to be operated independently of the other branches.

A carbon dioxide electrolytic device includes: an electrolysis cell including a cathode, an anode, cathode and anode flow paths, and a separator; a carbon dioxide source to supply carbon dioxide to the cathode flow path; a solution source to supply an electrolytic solution containing water to the anode flow path; at least one sensor to acquire at least one data of a data indicating a discharge amount per unit time of a liquid containing water to be discharged from at least one flow path and a data indicating a concentration of at least one ion in the liquid; a refresh material source including a gas source to supply a gaseous substance to the at least one flow path; and a controller programmed to stop the supply of the carbon dioxide and the electrolytic solution, and start supply of a gaseous substance from the refresh material source, in accordance with the at least one data.

A carbon dioxide electrolytic device of an embodiment includes: an electrolysis cell including a cathode, an anode, a carbon dioxide supply flow path, solution supply flow paths, and a separator; a rinse solution source which supplies a rinse solution to at least one of the solution supply flow paths and the carbon dioxide supply flow path; a first electric conductivity meter provided on a discharge port side from the electrolysis cell of at least one of the solution supply flow paths and the carbon dioxide supply flow path; and a rinse solution supply controller which controls stop operation of the rinse solution source according to a measurement result of the first electric conductivity meter.