There's an old joke that energy from nuclear fusion is 30 years away and always will be. For many decades, the industry did little to spoil the fun, running mammoth and unwieldy research projects, hoovering up a few billion dollars every science funding cycle and announcing breakthroughs that were scientifically interesting, but did little to move us towards actual production of electricity. Then three things happened. First, perhaps emboldened by Elon Musk's successful disruption of the space industry with SpaceX, a bunch of wealthy investors started to invest in much nimbler startups. Second, in December 2022, the National Ignition Facility at the US's Lawrence Livermore National Lab announced that it had finally got more energy out of a fusion experiment than it had put in. And third, AI exploded on the scene, offering dramatic acceleration in everything. These developments have turned the slow-moving world of fusion on its head. Over $14 billion has now flowed into fusion startups, and that is on top of the tens of billions already committed to national and international programs, like the International Thermonuclear Experimental Reactor (ITER) in France, the UK's Spherical Tokamak for Energy Production (STEP) and a variety of US national labs. This week on Cleaning Up, Michael Liebreich sits down with the director of one of those labs. Professor Sir Steven Cowley has been entrusted with leading one of the jewels in the US's scientific crown. He has dedicated his academic career to trying to make fusion energy work, and he's been known to joke that he hopes it does so before he dies. Michael and Steven discuss the breakthrough experiments that have shown fusion is possible, why getting from a successful experiment to a commercial power station is such a huge leap, and whether fusion can ever deliver affordable, dispatchable electricity. Steven puts forward the idea that fusion might have a Theranos moment, where over-promises in the industry come back to bite. Topics discussed in this episode: How fusion actually worksFrom experiments to electricityLaser versus magnetic fusionThe commercial fusion challengeHow AI can transform fusion researchFusion versus renewables and batteriesLeadership Circle Cleaning Up is proud to be supported by its Leadership Circle. The members are Actis, Alcazar Energy, Arup, Climate Imperative Foundation, Copenhagen Infrastructure Partners, Cygnum Capital, Davidson Kempner, EcoPragma Capital, EDP, Eurelectric, KKR, Mitsubishi Heavy Industries, National Grid, Octopus Energy, Quadrature Climate Foundation, Schneider Electric, SDCL and Wärtsilä. For more information on the Leadership Circle, please visit cleaningup.live. Links: Steven's TED Talk from 2009: https://www.ted.com/talks/steven_cowley_fusion_is_energy_s_future Steven’s talk at IPAM 2026: https://www.youtube.com/watch?v=USPd6zvA8pk Steven's talk at SOSV Steven’s talk at DeepTech Live, 2026: https://www.youtube.com/watch?v=f-kb3784BPYPrinceton Plasma Physics Lab: https://www.pppl.gov/ Hax Plasma Forge Incubator: https://hax.co/Aneeqa Khan on Cleaning Up: https://www.youtube.com/watch?v=zhEoMd7DEho Subscribe to our newsletter: https://cleaninguppod.substack.com/ Acronyms: ITER: International Thermonuclear Experimental Reactor STEP: Spherical Tokamak for Energy ProductionJET: Joint European TorusTFTR: Tokamak Fusion Test Reactor DOE: Department of Energy (US)FLiBe: Fluoride Lithium BerylliumNIF: National Ignition Facility Chapters: 00:00 Intro03:24 Career in fusion06:39 Commercial fusion10:26 Laser fusion18:40 Breeding tritium23:33 Fusion startups25:24 Laser versus magnets29:21 Magnetic fusion35:35 Reactor optimisation40:35 AI controls fusion44:52 Spherical tokamaks46:33 Reversed-field fusion49:24 Private fusion53:07 Fusion economics56:30 The future57:14 Outro
