The Paradius United Government is a spacefaring civilization who turned one of the other planets in their solar system, Zel Samine, into a giant energy-production facility to supply their needs.
Their sun gives off electromagnetic waves that cause Transformer energy consumption to multiply exponentially, making the system accessible only by shuttle (Transformers such as Cosmos or Astrotrain would not be able to make the trip). Ironically, though this feature usually renders their solar system off-limits to Transformers, the same strong energy fields which make Zel Samine a prime energy source shield its surface from most of those effects, and there's nothing to prevent Decepticons, once on Zel Samine, from constructing a Space Bridge and raiding every single Paradian power generating station...
The High Official of the Paradius United Government, which had been notably unhelpful in Optimus Prime's search for his missing comrades, generously offered to supply the Autobots' energy needs for the duration of their visit... provided they were willing to fight the Decepticons of course. Transformers: Call of the Future