The combination of solid oxide electrolysis cells (SOECs) with renewable electricity has enormous potential, but this requires the cells to be able to adapt to strong fluctuation conditions. This work directly combines fluctuating actual wind power with flat-tube Ni-YSZ/YSZ/LSCF-GDC SOECs to study the operational stability and energy consumption under wide fluctuation and constant current electrolysis. The results indicate that under an average electrolysis current density of 0.26 A cm−2, there is little difference in stability between fluctuation and constant current electrolysis. At a high current density of 0.58 A cm−2, the cells operating for 375 h under fluctuation conditions exhibit a larger degradation rate. The current density is dynamically switched between 0 and 0.93 A cm−2 to simulate actual wind turbine power fluctuations from 0 to 100 %. After rapid large-scale current switches for 2000 times in 375 h, little change is observed in the cell structure. Under fluctuating electrolysis, the minimum energy consumption for power-to-gas conversion in SOEC is 2.84 kWh/Nm3, while under constant current electrolysis, the lowest energy consumption is 2.67 kWh/Nm3. In summary, SOECs can efficiently and stably consume and store highly fluctuating renewable power and can also dynamically respond to wide power ranges from 0 to 100 %.