Nuclear energy has been around for decades, but its safety and the safety of its radioactive waste have always been a political nightmare. Still, some researchers have been redesigning nuclear reactors to make them safer in many ways, but these newer designs have yet to be scaled up and used commercially. Maybe someday nuclear technology will be ubiquitous, but it'll likely take a long time before anyone is willing to embrace fission/fusion energy that doesn't come from the Sun.
If you'd like to read more awesome and interesting stuff, check out this unrelated (but not entirely random!) Techdirt post