09e4b482_GUNDAM_G_GENERATION_WORLD_Wiki__Function
[Name in Japanese] EN [Name in English] EN [Function] 
Energy. The Unit cannot use its weapons if its remaining EN is less than the EN consumption of its weapons. EN can be replenished by putting the Unit in the Warship and wait for a Turn.
Stats and Weapons Explained - SD GUNDAM G GENERATION WORLD Wiki
Function