SSE 0 cost spells can be cast at 0 magicka

[Folling]

Casting spells with 0 magicka costs at 0 magicka doesn't seem like a common issue, but using perks from specific mods, which remove your magica regeneration entirely whilst also providing you with free to cast spells does make it necessary. E.g. "The Monarch" (or "Vanician Magic") and "Intuitive Magic" from ordinator.

 

Have a mod which lets you cast spells at 0 magicka if they also cost 0 magicka