How to add an energy meter inside a block GUI

Hello! I'm trying to make a tech mod, and I want to make a built-in energy meter inside a block GUI, or when you look at the block (HWYLA-like)

Like a GUI with at the top text saying "n FEV"

Is there a way to do this? All I've been seeing is to use global variables, but energy is a local variable (i think?).