This bubble makes your inertial mass smaller which allows you to reach velocity values above c

as long as the mass is non-zero, the value really does not matter, you would still need infinite energy

These generators are basically coils in warp nacelles protruding from the spaceship. These generate a subspace field, the so-called warp field or a warp bubble, which distort space-time and propels the bubble and spaceship in the bubble forward

https://en.wikipedia.org/wiki/Warp_drive#Star_Trek