https://www.bosch-hydrogen-energy.com/sofc/how-it-works/?gclid=CjwKCAiAxreqBhAxEiwAfGfndGCCDQcxzJqNAw05UepYtozwPJPLDWmm34FiWoLHizJj3pBXC4RSYhoCpKIQAvD_BwE

Electricity from a fuel cell is DC just like a solar panel.  The DC is sent to an inverter which generates 240VAC just like the power company.  A 100KW fuel cell system can supply 416Amps at 240VAC.   It looks to me like they just throttle up or down the hydrogen supply.  I am sure that there has to be a battery in there some where to compensate for the lead/lag of the fuel as a result of an instant on or off load, but not a large one like a solar system.