Thought-provoking anime?

Giant Robo poses an interesting idea. A world where people have found the perfect power source and everything else is obsolete. They have these things called Shizuma Drives, the simpliest way to describe them is they're like super batteries. They use them for everything. Computers, vehicles, and even something as simple as a ciggeratte lighter are all powered by the Shizuma Drive. They're also recycleable thereby making the world pollution free. But what happens when an entire world is dependant on a single energy source? I won't say anymore because I don't want to spoil it.

Don't be turned away from the series if you don't like giant robo battles, because inspite of the name and theme of the series, the story revolves far more around the characters and it's got ALOT of plot twists for only being a 7 episode OVA.

Jam it back in, in the dark.