After getting selected for an interview on campus, I interviewed with a current ELP Engineer. The interview consisted of your standard behavioral and historical questions as well as some technical questions. The interviewer was very professional and friendly. It was a very pleasant interview.
A couple of weeks later, I got an email saying that I was selected for a headquarter visit and a final round interview. This was located in Austin, TX. The actual interview was on a Friday, but they paid for a hotel up until Sunday morning so that the candidates can get a feel for Austin. They also took us out that Friday night and Saturday night to a dinner and then some bars.
On the day of the interview, all of the candidates got there early in the morning and had breakfast with our hosts while we listened to a presentation about the company. Then the interviews began.
There were 5 interviews, each with someone else, as well as a technical presentation. There was a historical, behavioral, technical, and 2 others based on the departments you were interested in. There was also a 10 minute technical presentation.
The behavioral interview was the standard "tell me about a time you..." interview questions. The historical interview was mostly about what my expectations were and what I was looking for in a job offer (salary, benefits, growth, culture, etc.). The technical interview was not as hard as I was expecting, and was about automation. The technical presentation is just about how you can communicate to an audience a technical subject. They don't really care what the subject is, as long as it is technical.
The company culture was great. It was very laid back and casual, and you would be working on very interesting problems.