I don't know about NRJ, but I rope dropped for FOP and walked right onto the ride. After I got out the wait was 45 minutes so I got back in line and rode it again (the wait was really more like half an hour.) So I rode FOP twice in an hour, no Fast Pass.
I would assume the wait for NRJ is similar, so plan on being at the park around 7:30. You go through security and then have to wait at the gate for the park to open. Hint: Just about every turnstile will be open at rope drop but people tend to cluster in the middle to wait, leaving the area at the far right mostly empty. Head for the turnstiles at the far right side and you might be at the front of the line!
Once the rope drops, walk briskly to the bridge - you will be stopped there until the rides open about 15 minutes after the park opens. Even if you're further back in the crowd you should be OK. Good luck!