For internship positions, it is easiest to have an internal employee referral. Also, the office within FERC which you are interested in must have a position available. Since I had an employee referral, my interview was pretty easy. It was a phone interview- they asked me what I knew about power (the more the better of course) and why I wanted to work at FERC. Also, saying that a full-time position at FERC is something you are very interested in helps a lot.
