Board Thread:Off Topic/@comment-11276487-20140524145048/@comment-24758713-20150210185439

23.255.143.14 wrote: The Last Dragonborn, remember, defeated a weakened Alduin, and their shouts are not at full- potential-- the Greybeards don't need to "recharge" their ability to shout.

It's only gameplay mechanics. Lore version states that the Last Dragonborn, like any other Tongue, could shout storms and cause massive havoks. In the lore version, of course, he doesn't need to wait for 60 seconds to shout Fus Ro Dah, he can continuesely do so.