Rotation Control Method for Improving the Electrocatalytic Reduction of CO₂ to Methanol under Wind Power Fluctuations

Energy storage systems based on off-grid fluctuated wind power offer an attractive approach through the electrocatalytic reduction of CO2 to methanol. Potential fluctuations derived from wind power cause various reduction products and decrease electrocatalytic efficiency in the CO2-to-methanol system. A periodic rotation control method of individual electrolyzers in electrolysis cells array with rated power (100%), fluctuating (0-100%), and standby (0%) status is proposed to solve potential fluctuation problems. O-2 volume is creatively used as an intermediate bridge to link potential and power so that a curve is fitted as a function of power-methanol Faradaic efficiency. The rotation control method improves the methanol Faradaic efficiency by similar to 18.5% compared to the conventional average and cumulation control method, while it reduces the coefficient of variation by 67.9% compared to the cumulation control method. This demonstration of the rotation control method provides a promising approach for the efficient utilization of wind energy with energy storage systems.