The same does not hold true for the bulk-based storage system, despite its higher density and hydrogen capacity on a materials basis. The slower desorption kinetics and heat transport of the bulk storage system combined with its less favorable thermodynamics lead to complete consumption of the 70 bar headspace hydrogen before the bed reaches the temperature needed for hydrogen release. As a result, the headspace pressure drops much more quickly than the nanomaterial storage system, dropping to 3.3 bar at 140 s; the fuel cell thus ceases to operate. Even charging the headspace to a higher pressure (100 bar, the DOE target maximum) provides insufficient hydrogen to achieve the bed temperatures required to successfully complete the drive cycle.