Hello! Yes, Steem and Steem power, they are the same, except Steem Power is Steem that has been Powered Up!
So with the Steem tokens, you can power up - basically this means to lock them away, put them in the vault - its basically like Proof of Stake. In this case, it takes 13 weeks to get steem power back into moveable steem tokens, or more accurately you can get 1/13th out every week for 13 weeks.
Why do we lock them in the vault? (aka power up?) Because this then controls the 'worth' of our upvote! The more steem power we have, the higher our upvote! (technically the upvote is not money, but just a claim on a fixed rewards pool).
I hope this helped, let me know if there are more questions, I might make a post ;p
Thanks for a great question, all questions are good, don't let anyone fool you, we were all new once!