I first had a phone screen, one more phone interview with multiple Xcel employees, then flown to Denver for two more in-person interviews before receiving an offer. It was enjoyable.
It was a panel with behavioral questions relevant to the position. I would suggest you have some specific examples ready. The interviews are hour long, with time for questions about the role.
Initial phone call, then in person interview with panel of two. Asked about seven questions. Friendly interviewers, tough questions. Called back within 2 weeks of the interview with results of the interview.