Most of the time, when people are talking about nuclear energy, they're talking about fission. Fission gets all the attention because it's already commercially available, and every so often there's an accident that makes the news and scares people away from all kinds of nuclear energy. But fusion is entirely different. Aside from the fact that no one has ever actually built a reactor that has generated more useful energy than needed to ignite atomic fusion (hydrogen bombs don't count!), fusion energy could be a great source of energy. We've covered fusion
a few times before, but here are just a few more interesting links on fusing atoms together.
If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post