After decades of research, in early December scientists at the Lawrence Livermore National Laboratory in California made a historic breakthrough in nuclear fusion by generating more energy than it took to create it. It’s a major scientific step because, according to experts, nuclear fusion has the potential to deliver clean and abundant zero-carbon energy. Richard Carlson is the director of energy policy at an environmental charity called Pollution Probe. Today on Front Burner, he'll explain how nuclear fusion uses the same process that powers the sun and why it could be a game changer for clean energy, if we can figure out how to harness it.