Java 1.20.1-5.1.19 Forge
This may also work with the Solar Generator or any other Energy Cube; I didn't test.
But yeah, having a passive source of power connected to it resulted in the Coercion Deriver just receiving power from thin air even after the Generator(s)/Energy Cube(s) were removed and all extra energy was exhausted.
The Fortron Capacitor had speed modules in it, if that matters at all?