Is there different strengths of black holes, and if so, could there be one that we could harness as an energy source

Question: Is there different strengths of black holes, and if so, could there be one that we could harness as an energy source that wasn't too dangerous?
- Keywords:
  black hole,
  space
Asked by anon-248476 to James on 15 Mar 2020.
- James Lees answered on 15 Mar 2020:
  
  Yes, the larger a black hole the ‘stronger’ it is. That means that it can pull in objects from further away.
  
  It is possible to use them as an energy source though it’s rather tricky as they are weird and dangerous object.
  
  I would point you to the following video for more information: https://www.youtube.com/watch?v=ulCdoCfw-bY

Question: Is there different strengths of black holes, and if so, could there be one that we could harness as an energy source that wasn't too dangerous?