In February 2024, the KSTAR nuclear fusion reactor, operated by the Korean Fusion Energy Institute (KFE) in South Korea, maintained a superheated plasma at 100 million degrees Celsius for 48 consecutive seconds. The 48-second record (2024) improved the previous record of 30 seconds (2021), placing Seoul at the forefront of a major technological competition where Asia challenges the West over the energy of the future. According to several specialized sources, this result represents a significant step in controlled nuclear fusion since the United States’ National Ignition Facility achieved ignition in December 2022.
This technical feat reveals a crucial geostrategic tension. The cost of renewable energy reached a historic tipping point in 2025, with solar and wind now representing the cheapest sources of electricity production in most regions of the world. Faced with this transformed economic reality, nuclear fusion must prove its commercial viability in a context where its astronomical costs collide with renewable alternatives in free fall.
The Essentials
- The Korean KSTAR reactor maintained a plasma at 100 million degrees for 48 seconds in February 2024, improving its previous record of 30 seconds
- South Korea aims for 1,000 seconds by 2026, while China and Europe advance on competing approaches
- Solar now costs 28-117 dollars/MWh and onshore wind 23-139 dollars/MWh, systematically surpassing fossil fuels
- ITER, the international fusion project, is pushing back its first plasma production from 2025 to 2033, with cost overruns of at least 5 billion dollars
A Decisive Step Toward Commercial Viability
KSTAR also maintained H-mode for 102 seconds, demonstrating that sustained fusion is possible. For fusion to generate electricity commercially, the plasma must be maintained for hundreds of seconds, ideally continuously. KSTAR’s advances mark substantial progress toward this objective.
This technical progression relies on crucial material improvements. Primarily thanks to the successful upgrade of KSTAR’s divertors with tungsten in 2023, the new tungsten divertors showed only a 25% increase in surface temperature under similar thermal loads compared to previous carbon-based divertors. This offers significant advantages for long-term, high-power heating operations.
The technical challenge remains considerable. KSTAR’s superconducting magnets operate at temperatures near absolute zero (-269°C), creating magnetic fields powerful enough to contain a gas 7 times hotter than the sun’s core. The irony is fascinating: the reactor must simultaneously be the coldest and hottest place on the planet.
Asia Leads a Fragmented Technological Race
KSTAR (South Korea): 48 seconds at 100 million°C — duration record (February 2024), EAST (China): exceeded the Greenwald limit — plasma density record (January 2026), ITER (France/35 countries): largest tokamak in the world under construction, first plasma planned 2027. Commonwealth Fusion (USA): 20 Tesla magnets, SPARC reactor planned 2027. Each program tackles a different aspect of the problem. KSTAR proves duration. EAST proves density. ITER will prove scale. SPARC will prove commercial viability. If all succeed, humanity will have the complete scientific foundation to build commercial fusion power plants in the 2030s.
The geography of innovation draws new balances. Where Europe bets on cooperative gigantism with ITER, Asia favors competitive national approaches. July 2017, China’s Advanced Superconducting Tokamak Experiment (EAST) (101.2 seconds) claims the record by containing a plasma for 100 seconds. December 2020, KSTAR reclaims the record by containing a 100 million degree plasma for 20 seconds. May 2021, China’s EAST reclaims the record by containing a 120 million degree plasma for 100 seconds.
This race reveals divergent strategies. While KSTAR focuses on the central ion temperature of the plasma, EAST focuses on the electron temperature of the plasma. Each country develops its expertise on different parameters, creating an involuntary technical complementarity that could accelerate global breakthroughs.
ITER Mired in Delays and Cost Overruns
Facing these Asian advances, the flagship Western project accumulates difficulties. Recently, the international nuclear fusion project known as ITER announced a significant delay to its schedule, pushing back first plasma production from 2025 to 2033. This delay is not merely a matter of time; it is also accompanied by a heavy financial burden, with projected cost overruns of at least 5 billion dollars. This revelation sent ripples through the scientific community and raised questions about feasibility.
The cost spiral is accelerating dangerously. The initial estimated costs for ITER were 12 billion dollars in 2006 (approximately 18 billion in 2023 dollars) at the project’s inception. By 2014, the estimate had increased to 21 billion dollars (approximately 27 billion in 2023 dollars). The most recent estimate, with the new completion date of 2039, is that the total cost will increase by an additional 5.4 billion dollars (in 2023 dollars).
These delays transform the competitive dynamic. ITER’s delay means the project could be overtaken by privately funded trials conducted by Commonwealth Fusion Systems LLC and Tokamak Energy Ltd., which use smaller versions of the same reactor and expect to begin prototype testing within this decade. The European model of international cooperation finds itself challenged by American entrepreneurial agility and Asian state determination.
The Economic Challenge Against Plummeting Renewables
Nuclear fusion faces a radically transformed economic context. Over the past decade, we have witnessed unprecedented cost reductions: photovoltaic solar costs have fallen 90% since 2010, while onshore wind costs have declined 69%. Renewable energy is significantly cheaper than fossil fuels in 2025. PV solar costs on average 4.4 cents per kilowatt-hour and onshore wind 3.3 cents/kWh (a 3% decrease from 2022).
This trajectory threatens the future economic relevance of fusion. PV solar is expected to see an additional 60% cost reduction by 2060, while onshore wind could decline 42% over the same period. By 2030, renewables should be approximately one-third cheaper than fossil fuels on average globally.
Faced with this competition, fusion struggles to demonstrate its economic viability. The cost of fusion technology is likely to fall more slowly than previously anticipated, raising doubts about its ability to compete with renewable energy. Expenses associated with fusion may not decrease as rapidly as those for batteries or solar energy.
The Strategic Bet of Private Investment
Despite these economic challenges, the private sector maintains its confidence. The nearly 3 billion dollars that CFS has raised to date represents approximately one-third of the total capital invested in private fusion companies worldwide, consolidating its leadership in the fusion industry. A number of fusion startup companies pioneered commercially-focused fusion development and raised 9.766 billion dollars by July 2025. American companies are now developing pilot plants — Helion Energy in central Washington State and Commonwealth Fusion Systems (CFS) in Massachusetts.
This private dynamic transforms timelines. The company wants to build a 400 MWe magnetically confined fusion power plant called ARC near Richmond, Virginia, and begin operating it in the early 2030s. CFS recently signed power purchase agreements with Google and Italian energy giant Eni for its first commercial fusion plant, ARC, expected to be operational in the early 2030s just outside Richmond, Virginia.
The multiplication of technological approaches diversifies risks. The diversity of technical approaches is at the heart of industry robustness. Magnetic confinement (tokamaks and stellarators) remains the dominant approach, used by 25 of 53 companies, but laser inertial fusion, magneto-inertial, hybrid electrostatic, and even muon-catalyzed fusion approaches are also being explored.
Tomorrow’s Energy is Decided Today
The Korean 48-second record marks less a technical victory than a geopolitical turning point. Nuclear fusion ceases to be a scientific challenge to become a matter of energy sovereignty. If fusion becomes commercial, countries without oil, without uranium, and without strong winds will have access to the same energy as industrial powers.
This potential redistribution of energy cards explains the intensity of current competition. The consensus of many scientists and business analysts is now convinced that fusion energy powering our homes is no longer a matter of if, but when, even if timeline estimates remain too optimistic. About 60 years ago, pioneering Soviet physicist Lev Artsimovich said that fusion energy would be ready “when society needs it.” The combination of advances in science, technology — supercomputing and superconducting magnets — and, critically, money from AI hyperscalers and others makes fusion energy a realistic option when the world demands far more electricity.
The race for fusion reveals as much about national ambitions as about technological challenges. Between the 48 Korean seconds and ITER’s decades of waiting, a new geography of innovation emerges where Asian agility challenges Western caution, while renewables impose their relentless economic pace.