Fusion energy has long been hailed as the holy grail because of its potential for limitless amounts of clean energy. But that promise has trailed reality for decades, with billions of dollars in research leading to few breakthroughs. Now there’s optimism that is about to change, partly because of new startups funded by the likes of Sam Altman, Jeff Bezos, and Bill Gates. Yahoo Finance went inside the country’s largest magnetic fusion facility for an exclusive look, to explore the challenges of bringing this technology to commercial use for the latest episode of NEXT. “The race is on to actually see who can develop this and who can get it to the masses the fastest,” said David Callaway, former editor-in-chief of USA Today and founder of Callaway Climate Insights, a news and information service focused on the business of climate change. The industry has now attracted more than $6 billion in funding to date, according to data from the Fusion Industry Association, with more than 40 startups aiming to become the first to commercialize nuclear fusion energy. The US government has set aside a record $1.48 billion for fusion research in the 2024 budget alone. Fusion energy has been considered a game-changer largely because of how the power source is generated. Unlike nuclear fission, which occurs when a neutron slams into a larger atom, splitting it into two, fusion occurs by taking two atoms and smashing them together to create a heavier atom. The process of fusion is equivalent to the process that powers the sun and other stars. Even more attractive to researchers, fusion doesn’t produce nuclear waste that can be weaponized. Despite the excitement around its potential, technological breakthroughs have largely been limited to government research labs – until now. In 2022 researchers at California-based Lawrence Livermore National Laboratory achieved ignition, generating more energy than the amount of energy it took to create the fusion reaction. But that gain lasted less than one-billionth of a second. Researchers are now looking to extend that reaction, a critical move in the next step towards re-creating the energy of a star that could provide unlimited clean energy for all. For more on our NEXT series, click here, and tune in to Yahoo Finance Live for more expert insight and the latest market action, Monday through Friday.