You’ll know you’ve entered a powered down area when the game notifies you, well, that you’re entering a powered down area on the top of your screen. Your mini-map on the bottom right corner will also produce static. On your map (), you’ll notice that island/areas to your right and the top are grayed out; those are the powered down areas.
Powered Down Areas
Entering these areas, much like the first game, will result in higher enemy encounter rates and be pitted against much stronger enemies, such as enemies behind shielded turrets and militants with mini-guns. It is suggested you go about this trophy once you’ve at least acquired the Ionic Vortex. You have a very limited supply in terms of restoring your energy, so if you're having trouble, come back to this trophy when you've reached at least Hero on your good karma playthrough; the passive ability restores your energy every time your bolts hit an enemy. Bio Leeching your enemies however, works just as fine.
Kill 50 enemies in these areas, and the trophy will unlock. Note that even if you die, your progress will still carry over. Remember, you must kill these 50 enemies when you're not in the middle or a story mission or side mission as the trophy description describes.