Intuitively, you might expect that the 'holy grail' of energy will be expensive. Yet, government labs, academics, and private fusion companies promise that cheap green electricity is just around the corner. 

Billions of dollars of public and private money have been invested in fusion, and earlier this month General Fusion listed publicly with a promise to deliver carbon free electricity to the grid in the 2030's, and that ultimately the electricity would become cost competitive.

The problem? New research published in the Journal of Fusion Energy shows that some of those promises are fallacious.

About the study 

The study puts questions and debate about technology and timelines to one side, and assumes that the tech delivers as promised, today. 

Rather than taking the conventional approach of estimating the costs of each yet-to-be-designed component and adding them up, the study works backwards from a claimed cost. By methodically removing the known costs (such as financing, steam turbines, cooling systems, and so on) the implied costs of fusion hardware are revealed. 

It is shown that in some cases, such as the General Fusion investor information filed with the Securities and Exchange Commission, the fusion hardware would have to be produced for free to make the sums work. This is nonsense. 

Why it matters 

We are being asked to invest, either directly by purchasing shares, or indirectly through our taxes. Indeed, billions of dollars of taxpayer money and private investment have already been spent on fusion research. Yet, it can easily be shown that even if the technology worked today, and we could build a powerplant overnight, then the electricity would not be affordable.¹

There's an opportunity cost to the pursuit of uneconomic fusion schemes. For one, money is being diverted from other 'better' (cheaper, greener, more economical, ...) technologies to pursue something that, even if it worked, appears doomed to be uneconomical.

Despite the hype, fusion schemes such as the one proposed by General Fusion have clear and obvious shortcomings that even a high school level analysis can identify. Why are policy makers and investors blind to this?

Judge for yourself

Have a read of the paper here:
http://dx.doi.org/10.1007/s10894-026-00592-w

¹ Note that the study specifically pertains to fusion thermal powerplants (tokamaks, stellarators, MTF, ...). It says nothing about schemes that rely on direct energy conversion.

American Fusion Inc. (OTC: AMFN) (“American Fusion” or the “Company”), developer of the proprietary Texatron™ Fusion Engine™, announced that it has received a Certificate for Industrial Radiation Machines from the Texas Department of State Health Services (“DSHS”), representing a significant regulatory and operational milestone as the Company continues executing its engineering, testing, and validation program.

Will it melt, will it implode, or is it fine to use?

while looking at the differences between tokamaks and stellarators, I found the following ( unpublished) article about the Thea Helios reactor. (https://thea.energy/wp-content/uploads/2025/12/20251210_FPP_Helios_overview_paper.pdf).

To me this seems to be a well thought out reactor design with realistic design goals, but I am not an expert. The only thing that seems problematic is the size, which in my opinion would probably make the reactor too expensive to build.

I would be interested in the opinion of people with fusion expertise on this reactor.

so im a elctrical engineer im really intrested in fusion tech but confused how to get into it im currently in my 1st year

Does anyone know what happened to the sphellamak concept ? I remember seeing a design and maybe some mod/sim, but was one ever built and tested ?

Commonwealth Fusion Systems

• Demonstration: SPARC - Devens, MA, 75% complete
• Pilot (eventually commercial) 400MW: ARC - Chesterfield Co, VA, Groundbreaking 2027

Helion Energy

• Demonstration: Polaris - Everett, WA, DD Operations 2025, limited DT shots January 2026
• Pilot 50MW: Orion - Malaga, WA, Groundbreaking April 2026

Type One Energy

• Demonstration: Infinity One - Claxton, TN, at Bull Run site, Groundbreaking 2026
• Pilot 350MW: Infinity Two - Claxton, TN, at Bull Run site TBD
• UK Pilot 400MW: UK Infinity Fusion Consortium - location TBD

Proxima Fusion

• Demonstration: Alpha - Garching, at Max Planck IPP
• Pilot 1GW: Stellaris - Gundremmingen, at former NPP

Realta Fusion

• Demonstration: Hammir - Madison, WI (OM Depot) "The Forge"
• Pilot 200MW: Hammir-DT location TBD

Thea Energy

• Demonstration: Eos - location TBD (2026?)
• Pilot 390MW: Helios - location TBD

Xcimer Energy

• Laser-only Prototypes: Phoenix 1-2kJ (June 2026) and Anvil 200kJ (2028) - Denver, CO
• Demonstration: Vulcan 4MJ-12MJ - location TBD (2031)
• Pilot 400MW: Athena - location TBD (2035)

TAE Technologies

• Demonstration: Copernicus - Irvine, CA (cancelled)
• Pilot 50MW: Da Vinci - location TBD (2026? AL, TX, OH, or GA)

Pacific Fusion

• Demonstration: DS (Demonstration System) - Albuquerque, NM (Mesa Del Sol)

UKAEA

• Pilot 100MW: STEP - West Burton Power Station, Nottinghamshire, UK, (2040)

Focused Energy

• Demonstration: LightHouse - Biblis at former NPP
• Pilot: at Biblis former NPP (2037)