In the dark energy gathering chamber of Black Star's spaceship.
A black metal sphere that was ten meters in diameter floated in the middle of the room. The surface of the sphere had many beehive-like holes lined up neatly along the surface with most of the holes being connected to a high efficiency energy transmitter cable that stretched to the wall.
The spaceship had many of these dark energy gathering chambers that were used to collect the dark energy when travelling in the universe. This black sphere was the dark energy converter. Under normal circumstances, the dark energy reactor was enough to sustain the spaceship for ordinary flight. Using such an energy collector was akin to harvesting solar energy for backup and for letting the energy reactor rest once in a while. It was also able to provide additional energy if required.