You can light it up with the lights on your exo suit, but there is a better way to turn on the lights and make the powerhouse a lot less scary.
From the power plant entrance in the large wide open area, go down the stairs. You should be in a dark rectangular room. Go to the door to the right of the room.
There will be an enemy in the room coming down the stairs with the YOSUKE Butterfly dual-wielding weapon. He is very strong and will immediately start attacking you with quick attacks. Dodge and then attack. Repeat until the enemy is defeated. It is recommended to use fast weapons, such as the one-handed sword, which can be obtained at the beginning of the game. Also aim your target at the opponent's right or left arm to get your own YOSUKE Butterfly weapon.
After winning, simply reload the terminal at the end of the room.
