The problem with geotermal for example is I think an issue of efficiency and cost vs benefits. You're not generating enough usuable energy without using expensive systems. Same with the other two. Thorium from what I've read in the past is promising but I forget off hand what the limitations were for that one.
By the way, I wasn't able to watch the video yet but I saw someone bad talking batteries and my reflexes kicked in. Going to watch it when I'm at home. The most interesting thing about my major to me is the study of power and power systems so definitely want to check that out.