What does it mean that btc is backed by power? As long as there is power there will be btc? Can I convert btc to power? Please elaborate

Edit: So I have to clarify that I made this post more from an economics and monetary theory point of view, but obviously it merges right into technology which I actually wasn’t expecting but that is obviously intrinsic to the concept of digital currency. I’m pleased with the discussions provided by those who actually took the time to answer my questions. Thank you