Fabric has no energy system. Anyway, you can do it if you want.

@BloCamLimb forge has a built-in energy system? or is fabric just more devided on the energy system?

Forge provides rich features and APIs, so it is suitable for developing large mod. Fabric is more just a lightweight loader, which itself can't help modding much. On Fabric, people commonly use several 3rd-party mod libraries for the energy system, fluid system and item transfer system.