Galaxy Express 999: Journey with Energy Beyond Space and Time

Planet Liger derives their energy from their star, whose entire surface area is covered with water

The 999 lands on a planet which relies purely on energy from its neighboring planet. The problem is that this other planet is constantly in turmoil and the imports are problematic.

Maetel and Tetsuro reach a planet called Ena. Maetel is very quiet, so much so that Tetsuro notices it. A volcano begins to erupt and a scientist saves the two. The scientist takes them to the power plant he works for. He begins to teach Tetsuro about the hi-tech plant. He then mentions the key energy-yielding element Enenium.