Physicists’ Critique: Helion Energy’s $15 Billion Nuclear Fusion Machine Cannot Work
Clip title: This $15 Billion Nuclear Fusion Machine Can’t Work, Physicists Say Author / channel: Sabine Hossenfelder URL: https://www.youtube.com/watch?v=wwB4hB9QJX8
Summary
The video discusses the current state of nuclear fusion energy, particularly focusing on the challenges faced by startups like Helion, despite a significant surge in private investment. The host, Sabine Hossenfelder, highlights that while fusion startups are continually pushing back their completion dates, a clearer picture is emerging regarding the viability of different technological approaches. She points out a “circularity” in the investment landscape, where major tech companies like Google, Microsoft (via OpenAI CEO Sam Altman), and Nucor are not only funding fusion startups but also signing contracts to purchase hypothetical future electricity, creating a speculative bubble around the industry. Helion, in particular, has seen its valuation soar to an astonishing $15.5 billion, tripling since January, despite growing scientific skepticism.
Helion Energy’s innovative approach involves a “field-reversed configuration” (FRC) where two plasma blobs are accelerated by magnets, collide, compress, and ideally fuse, with the goal of direct energy extraction. However, this method has recently come under harsh criticism from multiple independent scientific groups. John Slough, a pioneer in FRC research, argues that Helion’s aggressive approach runs into a “fundamental aspect” of FRC, leading to “catastrophic loss of flux” before fusion can occur. He explicitly states he “can’t see anything in the physics” that would allow their machine to work.
Further critiques come from a Max Planck Institute group, which contends that while initial energy transfer might favor heavy particles, this energy quickly redistributes, preventing nuclear ignition and rendering the approach impractical for power production. A French research group added that only a tiny fraction (around 1%) of the magnetic field energy actually heats the plasma, leading to massive energy loss and concluding that “net energy is never achieved” in realistic scenarios. Helion’s response to this criticism has been largely dismissive, claiming the critics are looking at an “old design plan” and that they “know how to fix the problem but won’t tell you how,” while quietly delaying their net power target from 2028 to 2029 or 2030.
Sabine concludes by expressing her personal skepticism about investing in Helion. She notes that other less experimental fusion approaches, such as magnetic confinement (e.g., Tokamaks, Stellarators), have shown more steady, albeit incremental, progress, while inertial confinement fusion (like that pursued by First Light Fusion) has largely stalled. Hybrid approaches, like the Z-pinch, represent a higher risk due to less understood physics but could potentially yield faster results if successful. Overall, she believes it is highly unlikely that any entity will achieve net power from nuclear fusion before the end of the decade, summarizing the situation as “understood physics is slow, poorly understood physics is fast… right up until you understand it.”
Video Description & Links
Description
Fusion startups keep postponing their dates, but it’s becoming clear who is doing well and who isn’t. Helion is valued at fifteen billion dollars, and three groups have now said their machine cannot work, one of them the researcher whose work it is based on. Let’s take a look.
Paper: https://doi.org/10.1007/s10894-026-00554-2 Paper 2: https://doi.org/10.1007/s10894-026-00565-z
sciencenews physics nuclearfusion energy technology
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Tags
hossenfelder, science with sabine, science humour, sabine hossenfelder, fusion energy, fusion power, fusion reactor, fusion power plant, net energy gain, Helion Polaris, David Kirtley, aneutronic fusion, helium-3, Commonwealth Fusion Systems, SPARC, ITER, Wendelstein 7-X, fusion startups, Microsoft fusion deal, clean energy, energy news, science news, physics news, technology news, is fusion power possible, when will we have fusion power, sabrina
URLs
- https://doi.org/10.1007/s10894-026-00554-2
- https://doi.org/10.1007/s10894-026-00565-z
- https://sabines-store.dashery.com/
- https://donorbox.org/swtg
- https://sciencewtg.substack.com/
Related Concepts
- nuclear fusion — Wikipedia
- Helion Energy — Wikipedia
- fusion energy startups
- private investment
- technological viability
- fusion energy — Wikipedia
- field-reversed configuration — Wikipedia
- plasma physics — Wikipedia
- magnetic confinement — Wikipedia
- tokamak — Wikipedia
- stellarator — Wikipedia
- inertial confinement fusion — Wikipedia
- z-pinch — Wikipedia
- net energy gain — Wikipedia
- speculative bubble — Wikipedia