When it comes to nuclear fusion energy, "How do we advance fusion as fast as possible?" asks the CEO of Commonwealth Fusion Systems. They've just raised $863 million from Nvidia, Google, the BIll Gates-founded Breakthrough Energy Ventures and nearly two dozen more investors, which "may prove helpful as the company develops its supply chain and searches for partners to build its power plants and buy electricity," reports TechCrunch. Commonwealth's CEO/co-founder Bob Mumgaard says "This round of capital isn't just about fusion just generally as a concept... It's about how do we go to make fusion into a commercial industrial endeavor."The Massachusetts-based company has raised nearly $3 billion to date, the most of any fusion startup. Commonwealth Fusion Systems (CFS) previously raised a $1.8 billion round in 2021... CFS is currently building a prototype reactor called Sparc in a Boston suburb. The company expects to turn that device on later next year and achieve scientific breakeven in 2027, a milestone in which the fusion reaction produces more energy than was required to ignite it. Though Sparc isn't designed to sell power to the grid, it's still vital to CFS's success. "There are parts of the modeling and the physics that we don't yet understand," Saskia Mordijck, an associate professor of physics at the College of William and Mary, told TechCrunch. "It's always an open question when you turn on a completely new device that it might go into plasma regimes we've never been into, that maybe we uncover things that we just did not expect." Assuming Sparc doesn't reveal any major problems, CFS expects to begin construction on Arc, its commercial-scale power plant, in Virginia starting in 2027 or 2028... "We know that this kind of idea should work," Mordijck said. "The question is naturally, how will it perform?" Investors appear to like what they've seen so far. The list of participants in the Series B2 round is lengthy. No single investor led the round, and a number of existing investors increased their stakes, said Ally Yost, CFS's senior vice president of corporate development... The new round will help CFS make progress on Sparc, but it will not be enough to build Arc, which will likely cost several billion dollars, Mumgaard said. "As advances in computing and AI have quickened the pace of research and development, the sector has become a hotbed of startup and investor activity," the article points out. And CEO Mumgaard told TechCrunch that their Sparc prototype will prove the soundness of the science — but it's also important to learn "the capabilities that you need to be able to deliver it. It's also to have the receipts, know what these things cost!"Read more of this story at Slashdot.