So what am I supposed to do with energy kits?

I can't open them and it doesn't give the option to liquidate . They're filling up my inventory and my crafting station.

You can use them during the next event.

Keep them to use for energy when the next special event comes around. Events like winterfest in AL use energy to play the dungeon and regenerate every 8hrs so these would be a great help if you had lots.