FOG BLOG U.S. NEWS LOG: JENNIFER GRANHOLM , ENERGY SECRETARY ABOUT BREAKTHROUGH ON NUCLEAR FUSION!

Energy secretary shares when nuclear fusion energy might be widely used The U.S. Department of Energy announced a breakthrough in nuclear fusion on Tuesday that puts the world one step closer to harnessing an abundant energy source free from carbon emissions and long-lived radioactive waste.

U.S. Energy Secretary Jennifer Granholm confirmed that scientists achieved a reaction that created more energy than was used — known as a net energy gain — at the federally-funded Lawrence Livermore National Laboratory in California.

“Last week at the Lawrence Livermore National Laboratory in California, scientists at the National Ignition Facility achieved fusion ignition,” Sec. Granholm said. “It’s the first time it’s ever been done. … Simply put, this is one of the most impressive scientific feats of the 21st century.”

Such a development carries broad implications for renewable energy and long-term solutions to replace fossil fuels, though the benefits are still decades away.

“It'd be an enormous game changer,” Constellation Energy CEO Joe Dominguez told Yahoo Finance Live on Monday (video above). “We've been chasing this for a long time. But the developments we saw out of Lawrence Livermore are, I think, the best developments on fusion energy that we've seen since the work at Princeton probably 30 years ago with the TFTR [Tokamak Fusion Test Reactor]. So it's very exciting. It's transformational.”

A nuclear fusion reaction, which is what keeps the sun and other stars burning, occurs when the nuclei of two atoms fuse into one atomic nucleus. When that happens, the excess mass converts into energy. (The reverse process, nuclear fission, powers existing nuclear power plants and bombs.)

Scientists have been working to achieve sustained nuclear fusion since the Lawrence Livermore Laboratory was founded in the 1950s, but replicating the conditions found within the massive cores of stars in labs on earth has proven to be a seemingly intractable problem.