The Power Droid is a unit in Star Wars: Galactic Battlegrounds: Clone Campaigns that is available at the Power Core in Tech Level 1. It is a mobile Power Core that can wander around and provide power to the player's buildings. It has no attack.
Power Droids have less range than Power Cores, and cost population, but they cost less carbon and can move around. They can, for example, be used when the player needs to quickly bring back power to a part of the base where the opponent has knocked down a Power Core, or to bring temporary power to remote buildings (for example, speeding up research time at Nova Crystal Proc Ctrs or Ore Proc Ctrs that are located away from the main base).
"In Tech Level 2, civilisations gain access to a Power Droid, a slow-moving unit that functions as a mobile Power Core. Power Droids have no offensive capabilities. They also have less range than a standard Power Core, and are considerably less resistant to damage, so their strength and purpose lies in their ability to move – as well as in their relatively low cost. Power Droids may be enhanced through some of the new technologies available from Power Cores at later Tech Levels."
The manual states that the Power Droid is available in Tech Level 2. It's actually available in Tech Level 1.