If Pokemon League Headquarters stadium is in play, how many energy are needed for energyless attacks like Cleffa's "Grasping Draw" attack?

Any attacks that normally cost no energy now require at least one energy to be attached when Pokemon League Headquarters is in play. However, if an effect like Cramorant's "Lost Provisions" Ability sets an attack's cost to zero energy, Pokemon League Headquarters does not add an additional energy requirement to it.

Relevant cards

SV3_80

SWSH11_50