So what I was thinking about with the collectors:
The ship has small steam turbines positioned in the nacelles and larger ones in the engineering hull for power generation. To jump to warp, the warp field is generated, and the warp nacelles start up. I have an idea that the "warp coils" could possibly be spinning superconductors. Maybe. But anyway, when the ship reaches warp speed and begins sweeping up radiation and other junk, it could be absorbed SOMEHOW, and used to heat a liquid to steam in the nacelles, running a turbine to generate electricity to spin the coils, essentially a self-propelled space vacuum-cleaner. Any energy that can't be used could be stored, or vented off slowly (Maybe that's why the nacelle "caps" and later the nacelle grilles glow?)
Possibly bits of the warp field are somehow pinched off and channeled to the nacelles periodically, the way a cell pinches off bits of its membrane to act as food containers.