Exactly. An IDSU is portable power. It's like the EU version of a tesseract that holds 1Billion EU (Too bad it can only output 2kEU/t though.)
I do not understand how that my reply is an "exactly" reply possibility. A remote charging solution is going to be GREATLY cheaper than an IDSU (you can make a remote charging system within your first day of playing easily), whereas an IDSU is an endgame project at the earliest.