Every day, one story that matters, broken down into three numbered scenarios, each with its own probability. Never fixed — it shifts as the situation changes.
Scénario
Tuesday, grand futur
Nuclear Fusion: The Promise Finally Kept?
Publié le 15 septembre 2026
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The question at hand
After the first US commercial license (August 31) and record private funding, will fusion deliver on its promise this decade, or keep pushing back the deadline like ITER?
The facts
On August 31, 2026, the US state of Tennessee issued the world's very first commercial license for nuclear fusion. It was granted to a startup, Type One Energy, for a project called Project Infinity, on a site in Clinton that once housed a coal plant. This license is no administrative detail: it is the first time a regulator has created an entire framework, specific to fusion, to legally authorize the construction and operation of such a plant. Until now, no country in the world had this framework ready. The target plant, Infinity Two, is expected to produce 400 MW of electricity fed into the grid, from a gross reaction of 800 MW obtained by deuterium-tritium fusion.
The timeline announced by the company itself remains cautious on paper but ambitious in practice: a training prototype, Infinity One, is targeted around 2029, and full startup of Infinity Two by 2034. These dates are not certainties, only goals set by a private company that must convince its investors. But they are part of a broader trend: in the twelve months through July 2026, the private fusion sector raised a record $4.48 billion, up 69% year-on-year, according to the annual report of the Fusion Industry Association published on July 13, 2026. Since 2021, the cumulative total has reached $14.24 billion, raised by 56 companies that now employ over 16,000 people worldwide.
The same report provides a useful indication of the sector's mindset: 71% of companies surveyed still believe their first plant will deliver commercial electricity in the 2030s. This figure should be read with caution, as it reflects stated intentions, not achieved results. The main obstacle cited remains funding, but major technical challenges also persist: reactor energy efficiency and material resistance to the neutrons released by the reaction. These are real engineering problems, unsolved at scale, which explain why no one in the sector promises an immediate revolution.
To measure the gap between promise and reality, just look at ITER, the international public megaproject born in 1985 at a summit between Reagan and Gorbachev, headquartered in Cadarache, France. ITER initially aimed for first plasma in 2018. By 2016, that target had already slipped to 2025. On July 3, 2024, a new official schedule pushed first plasma back to 2034 — the same year as the full startup target for Infinity Two in the United States — with an announced cost overrun of €5 billion. Full deuterium-tritium fusion is not expected until 2039.
Understanding it
Why unprecedented scientific megaprojects almost always run over schedule.
Building a first-of-its-kind machine is like constructing a bridge of an entirely new type: no prior plan guarantees every part will work on the first try. ITER is a direct illustration, with its target pushed from 2018 to 2025 and then to 2034, delayed by the pandemic and defects requiring the replacement of 23 kilometers of piping. This is not a project failure, but the usual price of the unprecedented.
The causes of these delays are not due to project abandonment: ITER is making concrete progress, with a fifth plasma chamber module installed in May 2026 and a first superconducting magnet already cooled to -269 degrees. But the Covid-19 pandemic disrupted supply chains, and manufacturing defects forced the replacement of about 23 kilometers of cooling piping on the thermal shields. These are typical problems of a project building, for the first time in the world, parts that no factory had ever produced at this scale. China is also advancing on its own public trajectory: the toroidal magnet of the future tokamak BEST, in Hefei, weighs 582 tons and completed its final tests in early August 2026, with a net power demonstration targeted around 2030.
It is this contrast that makes the decade's outcome uncertain and justifies three possible readings of what comes next. On one side, a private industry in full acceleration, driven by competition among 56 companies and historic funding, including new stock market listings planned this year for two of them. On the other, a public megaproject with no direct competitor, funded by 35 countries, which has just announced its second major delay in eight years. Between these two trajectories, nothing guarantees that one will prevent the other from derailing in turn — nor that the first technical success will suffice to shift the global electricity mix, which even the most optimistic analysts in the sector do not see transformed before 2050.
Understanding it
Why fusion is now advancing on two opposing logics at the same time.
ITER resembles a cathedral built by 35 countries with no competitor or commercial clock, while the 56 private fusion companies are like runners who must cross the finish line quickly to reassure their investors. The same technology, fusion, thus produces two very different timelines: the cautious, often delayed one of the public sector, and the optimistically stated one of the private sector.
The next milestones that will decide
12027Target completion of Chinese tokamak BEST (Hefei)
22029Target startup of Infinity One, US prototype by Type One Energy
32030Target demonstration of net fusion power in China (BEST)
42034Target full startup of Infinity Two (Tennessee) AND target first plasma of ITER — same year
52035Target grid electricity via CFETR (China) and target commercial plant by Renaissance Fusion (France)
Five deadlines, on three continents, that will tell whether fusion's timeline finally holds or slips again.
Global private fusion funding (12 months to July 2026)$4.48B +69% year-on-year, cumulative total $14.24B since 2021 — FIA report, July 13, 2026
First plasma at ITER (public megaproject, France) — target year2034 vs. 2025 announced in 2016, and 2018 originally — +€5B cost overrun, announced July 3, 2024
Favorable, stable, or degraded
La fusion nucléaire va-t-elle enfin devenir une énergie réelle, ou rester une promesse repoussée ?
What we're assessing
FavorableLes projets pilotes tiennent leurs délais et la fusion commence à peser réellement sur le mix électrique mondial d'ici 2040.
StableLes jalons s'enchaînent avec quelques années de retard, et des centrales de démonstration existent vers 2035 sans bouleverser le mix énergétique mondial avant 2045-2050.
DégradéUn projet phare subit un nouvel échec comparable à celui d'ITER, le financement privé se contracte, et la fusion repasse après 2050.
Favorable
20%
Unlikely
Pilot plants meet their deadlines
In this scenario, commercial pilot projects — Type One Energy, Commonwealth Fusion Systems, Helion, and the Chinese tokamak BEST — broadly meet the dates they announce, between 2029 and 2035, without any new major delay comparable to ITER's. Infinity Two starts up on time in 2034 in Tennessee, BEST delivers its net power demonstration around 2030, and China advances CFETR toward 2035. A first fusion electricity then truly begins to weigh on the global electricity mix by 2040, which would be a break from the sector's 40-year history.
This scenario assumes the private sector escapes the cycle of delays that has plagued ITER since 1985, even though its machines are also world firsts technically. This is the main difference from the stable scenario, where schedule slips remain the norm even in the private sector, and from the degraded scenario, where a failure eventually hits a flagship project. Here, commercial pressure and competition among 56 companies work in favor of meeting deadlines rather than against.
Indicators affected
Financement privé mondial de la fusion4,48 Md$↑continue de croître sans contraction
The France angleRenaissance Fusion would then meet its own target for a commercial plant in 2035, alongside ITER in Cadarache. ↑ Rather favorable for France.
Stable
50%
Likely
Milestones advance, but with usual delays
In this scenario, technical milestones continue to follow one another — licenses, prototypes, first plasmas — but with the few-year slips already seen throughout fusion history. Demonstration plants do exist by the mid-2030s, in Hefei, Tennessee, or elsewhere, but they remain rare, costly, and often behind their original schedule. No real shift in the global energy mix occurs before 2045-2050, which aligns with the projections of the sector's most cautious analysts.
This scenario is closest to what the Fusion Industry Association report already shows: real optimism among companies (71% still target the 2030s) combined with unresolved technical challenges, such as material resistance to neutrons. It differs from the favorable scenario in that delay becomes the rule rather than the exception, without falling into the widespread failure of the degraded scenario — fusion progresses, just slower than promised.
Indicators affected
Premier plasma d'ITER2034→cible tenue, sans nouveau report supplémentaire
The France angleITER continues to advance in Cadarache, module by module, without new delays but also without acceleration. ↓ Rather unfavorable for France.
Degraded
30%
Likely
Another failure pushes fusion past 2050
In this scenario, one or more flagship projects, private or public, suffer another major delay or a technical and financial failure comparable to ITER's, whose target has already moved from 2018 to 2025 and then to 2034. Private funding, after several consecutive record years, contracts as investors lose patience with the lack of concrete results on the power grid. Fusion then falls back into the historical cycle of unfulfilled promises that has characterized it for forty years, with the deadline pushed past 2050.
This scenario does not require a complete abandonment of the sector — ITER, for example, would likely continue to advance slowly, as it has since the 1980s. The difference from the stable scenario lies in the scale of the shock: here, it is a truly central project, not just a slipping schedule, that falters, and it is this confidence shock that closes, at least temporarily, the tap of private funding that had just set a record.
Indicators affected
Financement privé mondial de la fusion4,48 Md$↓recul après plusieurs années de records
The France angleA new delay for ITER in Cadarache would also undermine the credibility of Renaissance Fusion and the nascent French sector. ↓ Rather unfavorable for France.
Ordres de grandeur indicatifs pour les 3 scénarios ci-dessus, estimés avec l'information disponible à la publication et réévalués si la situation change — jamais des prévisions garanties. Learn more about our method →
Key takeaways
Can nuclear fusion finally keep a timeline, after 40 years of postponed promises?
On August 31, 2026, Tennessee issued the world's first commercial fusion license, while the private sector raised $4.48 billion in a year — a record.
The most likely scenario (50%): real but still delayed technical milestones, with no major impact on the global power mix before 2045-2050.
To watch: the completion of China's BEST tokamak, targeted for late 2027, the first major timeline test after the funding record announcement.
Fairly negative
Our assessment of the impact for France: fairly negative. The stable scenario (50% probability) keeps ITER at Cadarache on its already delayed timeline to 2034, without real acceleration. The degraded scenario (30%) would directly weaken the credibility of the French site and the young private industry, such as Renaissance Fusion. Only the favorable scenario (20%), the least likely of the three, would clearly benefit France.
