Nuclear fusion is the same process that powers the Sun and stars weforum.org – merging light atomic nuclei (like hydrogen) to form heavier ones and release enormous energy. In theory, fusion could provide virtually limitless, climate-friendly energy: it uses abundant fuel (hydrogen isotopes from water or lithium) and produces little radioactive waste compared to conventional nuclear power. Unlike splitting heavy atoms (fission), which leaves long-lived waste, a fusion reaction yields mostly harmless helium and short-lived neutrons weforum.org, euro-fusion.org. Recent advances have reignited a “fusion frenzy” – a global race among national labs and startups to tame the power of the Sun on Earth. Scientists, entrepreneurs and policymakers increasingly ask: could fusion finally revolutionize our energy systems?
A Brief History of Fusion Research: Fusion has fascinated scientists for a century. In the 1920s astrophysicists (like Arthur Eddington) first proposed that stars shine by fusing hydrogen into helium euro-fusion.org. The first laboratory fusion (of heavy hydrogen) was achieved by Rutherford in 1934. But practical fusion reactors came later. In 1950 Soviet physicists Sakharov and Tamm proposed the tokamak – a magnetic “doughnut”–shaped fusion device euro-fusion.org. (At about the same time, US physicist Lyman Spitzer developed an alternative “stellarator”.) These magnetic-confinement ideas dominated fusion research thereafter. By the 1970s, international collaboration kicked in. Europe pooled efforts to build JET (Joint European Torus) – design work began in 1973, and the first plasma was achieved in 1983 euro-fusion.org. In 1985 the idea for ITER (International Thermonuclear Experimental Reactor) was born at the Reagan–Gorbachev summit, aiming for an unprecedented multinational fusion testbed euro-fusion.org. Throughout the 1980s–90s, tokamaks like JET and Japan’s JT-60 set performance records; for example, in 1997 JET used a 50-50 mix of deuterium–tritium fuel to produce 16 MW of fusion power (an output over half of its heating input) euro-fusion.org. Meanwhile, the U.S. and others explored inertial confinement fusion (using giant lasers). But despite decades of progress, no reactor had yet produced more energy than it consumed – fusion remained a scientific challenge “always 30 years away,” as the saying went.
How Fusion Works (and How It Differs from Fission): In simple terms, fusion combines light nuclei – usually isotopes of hydrogen called deuterium and tritium – into a helium nucleus, releasing energy via Einstein’s E=mc². This requires incredible conditions: fuel must be heated to ~150 million °C to overcome the electrostatic repulsion of nuclei weforum.org. The fuel becomes a plasma (an ionized gas), confined either by strong magnetic fields (tokamaks or stellarators) or by imploding fuel pellets with intense lasers (inertial fusion). In a tokamak, superconducting magnets create a magnetic “bottle” to hold the hot plasma away from the reactor walls. In inertial fusion, powerful lasers symmetrically compress a tiny capsule of fuel until fusion ignites.
By contrast, nuclear fission (used in today’s reactors) splits heavy atoms (like uranium or plutonium) into smaller pieces, releasing energy and many neutrons. Fusion has several key advantages over fission. Fusion fuel is far more abundant and energy-rich. For example, a U.S. National Lab notes that fusion yields about four times more energy per kilogram of fuel than fission, and nearly four million times more than burning coal or oil datacentremagazine.com. The fuel isotopes (deuterium and tritium) can be extracted from seawater and lithium, whereas fission requires scarce, mined uranium. Fusion’s byproducts are less troublesome: mostly helium (an inert gas) and high-energy neutrons; there is no risk of a runaway chain reaction or meltdown. Importantly, fusion produces little long-lived radioactive waste. (Tritium itself is radioactive but has a short half-life, and other induced radioactivity in structures decays much faster than fission waste.) In short, fusion promises a cleaner and safer alternative, potentially supplying vast baseload power without greenhouse gas emissions weforum.org, euro-fusion.org.
Major Fusion Projects: Governments and labs worldwide are pursuing large-scale fusion experiments:
- ITER (France, international): The most ambitious project is ITER, a giant magnetic fusion reactor under construction in southern France. ITER is funded by 33 countries (EU, US, China, Russia, Japan, India, Korea) and aims to demonstrate the feasibility of fusion power on a large scale world-nuclear-news.org. It is designed to produce 500 MW of fusion power for 400 seconds using 50 MW of input heating world-nuclear-news.org – a tenfold energy gain if successful – but won’t generate electricity itself world-nuclear-news.org. Its goal is to prove the physics and technology: first plasma is now targeted for 2035 (a delay from original 2025) world-nuclear-news.org. Construction began in 2010, with most major components now assembled. ITER has faced typical “first-of-a-kind” delays (pandemic shutdowns, engineering problems) world-nuclear-news.org, but it remains the centerpiece of global fusion R&D.
- JET (UK/Europe): The Joint European Torus in Culham, UK, was for decades the world’s largest operational tokamak. From 1983 until its retirement in 2023, JET pioneered the use of true fusion fuel (a deuterium-tritium mix). In its final experiments (late 2023), JET set a new record by releasing 69.3 MJ of fusion energy over 5 seconds euro-fusion.org. (By comparison, this dwarfs prior tokamak records and even exceeded a recent high-yield shot at the U.S. National Ignition Facility.) JET’s achievement confirmed scientists’ control over fusion plasmas and will directly inform ITER’s operation euro-fusion.org. UK officials hailed JET’s “swansong” experiment as evidence that “we are closer to fusion energy than ever before” euro-fusion.org.
- NIF (USA, LLNL): The National Ignition Facility in California takes the laser-driven approach. In December 2022, NIF made headlines by achieving fusion ignition: its lasers delivered 2.05 MJ to a fuel capsule and produced 3.15 MJ of fusion energy – more energy out than in lasers.llnl.gov. This was the first time any fusion experiment reached that milestone. Significantly, LLNL researchers have since replicated and surpassed that result in 2023: a July shot yielded 3.88 MJ (from 2.05 MJ in), and an October test delivered 3.4 MJ (from 2.2 MJ in) lasers.llnl.gov. These repeated target gains (fusion output exceeding input) show that ignition can be reliably achieved. However, NIF’s lasers consume about 100 times more energy overall than they deposit in the target, so NIF itself is not an energy-producing system lasers.llnl.gov. Instead, it validates fusion physics and guides “inertial fusion” designs.
- EAST and KSTAR (Asia): China’s EAST (“Artificial Sun”) tokamak and South Korea’s KSTAR tokamak are pushing long-duration plasmas. In January 2025, EAST sustained high-performance fusion plasma for 1,066 seconds (over 17 minutes) – a new world record english.cas.cn. This beat its own 2023 record of 403 seconds. Such long pulses are crucial for future power plants. KSTAR achieved its own milestones (over 100 seconds at >100 million °C in 2022). These experiments prove that superconducting tokamaks can hold burning plasmas, informing designs like China’s future fusion pilot plant (CFETR) and the UK’s STEP.
- Other national efforts: Japan is commissioning its JT-60SA tokamak (a successor to older JT-60) with EU help. Canada’s ITER Project (Fusion for Energy) and projects in Russia, India and elsewhere also contribute. Meanwhile Germany’s Wendelstein 7-X stellarator (a different magnetic geometry) is experimenting with alternative confinement methods.
The Private-Sector Fusion Race: In recent years dozens of startups have joined the fusion effort, energizing the field with private capital and innovation:
- Commonwealth Fusion Systems (CFS, USA): A spin-off from MIT, CFS is building SPARC, a compact tokamak using cutting-edge superconducting magnets. SPARC’s goal is to demonstrate net-positive fusion energy at small scale. Construction is well underway in Massachusetts; first plasma is targeted around 2026 reuters.com. CFS has raised over $2 billion, with major backers (Italy’s ENI, Singapore’s Temasek, Norway’s Equinor, etc.) reuters.com. In December 2024 CFS announced plans for ARC, a 400 MW pilot power plant in Virginia to supply electricity to the grid by the early 2030s reuters.com. (ARC would be “the world’s first grid-scale fusion plant” if realized.) CFS CEO Bob Mumgaard cautions there’s “no guarantee” it will all go to plan, but investors seem confident reuters.com.
- TAE Technologies (USA): TAE (formerly Tri Alpha Energy) uses a Field-Reversed Configuration (FRC) approach with aneutronic fuel. In April 2025 they reported a major “Norm” breakthrough: using a novel neural-beam injection, their latest prototype achieved stable plasma at temperatures above 70 million °C datacentremagazine.com. This advance “dramatically reduces complexity and cost,” the company says. Google has been partnering with TAE (applying AI to optimize its plasmas) and led a recent funding round datacentremagazine.com. TAE’s CEO, Michl Binderbauer, emphasizes fusion’s potential: “Fusion has the potential to transform the energy landscape, providing near-limitless clean power” datacentremagazine.com. (TAE also highlights that fusion yields ~4× more energy per mass than fission datacentremagazine.com, and that their D–³He approach emits mostly charged particles instead of neutrons datacentremagazine.com.)
- Helion Energy (USA): Backed by investors including Microsoft and OpenAI’s Sam Altman, Helion is developing a pulsed fusion system using a D–³He fuel cycle and direct electricity recovery (no steam turbine). Its “Trenta” prototype already exceeded 100 million °C in 2021 world-nuclear-news.org, and its latest machine Polaris began operations in 2024 world-nuclear-news.org. In July 2025 Helion broke ground on its Orion power plant in Washington state world-nuclear-news.org. Orion (50 MW net) is expected online by 2028 world-nuclear-news.org, and Microsoft has signed an agreement to buy 50 MW from it starting in 2028 businessinsider.com, world-nuclear-news.org – the first-ever commercial fusion power purchase. Helion’s CBO, Scott Krisiloff, notes: “We have never been able to harness [fusion] on Earth in a way that we can produce electricity from it… but Helion says its device does not use cryogenic superconducting magnets and directly converts fusion energy to electricity world-nuclear-news.org.”
- Others: Numerous startups are pursuing diverse fusion concepts. Canada’s General Fusion (backed by Jeff Bezos) is exploring magnetized-target fusion; UK’s Tokamak Energy is building small spherical tokamaks with high-field magnets; Princeton-based Helicity (now Zap Energy) and others test linear coaxial reactors. Each claims innovations in confinement, materials or reactor design.
Recent Breakthroughs (2023–2025): The last two years have seen several high-profile milestones:
- Fusion Ignition and Repeats: At Lawrence Livermore’s NIF, the 2022 ignition shot has been replicated and even improved. A July 2023 experiment yielded 3.88 MJ fusion output (with 2.05 MJ laser input) – the highest ever lasers.llnl.gov. NIF has now demonstrated ignition multiple times, showing its results are reproducible lasers.llnl.gov. These experiments confirm that fusion ignition physics works, though they remain tiny compared to the facility’s total energy use.
- New World Records: In early 2024 JET’s final experiments delivered a record 69.26 MJ of fusion energy in one pulse euro-fusion.org. This “new world record” was achieved in a sustained 6-second burn using only 0.21 mg of fuel euro-fusion.org – about the energy of burning 2 kg of coal. Meanwhile, China’s EAST tokamak raised the bar on pulse duration: in January 2025 it held a high-power plasma for 1,066 seconds (nearly 18 minutes) english.cas.cn, shattering its previous 403-second record. These results demonstrate that long, stable plasma operation (needed for power plants) is becoming possible.
- Private Lab Wins: TAE’s “Norm” device (spring 2025) and Helion’s Polaris (2024) represent private-sector proofs-of-concept at fusion conditions datacentremagazine.com, world-nuclear-news.org. CFS has installed much of SPARC’s machinery (including next-gen superconducting magnets) and plans first plasma in about two years. Helion is building its first plant on a factory timetable. Each week seems to bring news of new contracts or investments – for example, Google’s recent funding of TAE and Microsoft’s Helion deal illustrate growing corporate bets on fusion.
Expert Perspectives: Leading scientists and policymakers are enthusiastic but cautious. At COP28 in late 2023, U.S. Climate Envoy John Kerry said “fusion [has] the potential to revolutionize our world” weforum.org, and 35 nations signed an initiative to boost fusion R&D weforum.org. Kim Budil, director of LLNL, notes that private innovation is accelerating, but admits actual power plants might still be “two or three decades away” weforum.org. EUROfusion leaders remark that JET’s success “instils greater confidence” in fusion’s development euro-fusion.org. CFS’s Bob Mumgaard argues more investment is justified: “if you don’t prepare, it [fusion] won’t [succeed]” reuters.com. Fusion proponents frequently highlight its benefits: for example, EUROfusion’s CEO Ambrogio Fasoli says recent experiments “deepen our understanding” and raise confidence that ITER and future DEMO power plants will work euro-fusion.org. TAE’s Michl Binderbauer gushes that fusion offers “near-limitless clean power” in compact machines datacentremagazine.com.
Challenges to Commercialization: Despite the excitement, huge challenges remain. To ignite fusion, fuel must reach ~150 million °C and remain confined long enough – a feat requiring extreme engineering weforum.org. Materials must tolerate intense neutron radiation and heat flux. Economically, reactors must become far cheaper: ITER’s cost overruns underscore the scale and expense of fusion engineering world-nuclear-news.org. Fuel supply is nontrivial: tritium is radioactive and scarce, so future plants will need lithium blankets to breed it. Perhaps most fundamentally, net power is still unproven. As Reuters notes, fusion’s “top technological question” is how to get more energy out than is put in reuters.com. The U.S. DOE calls last year’s breakthrough “a major scientific breakthrough decades in the making,” underscoring how long the journey has been theguardian.com. UK minister Andrew Bowie warned that even JET’s success is “just the beginning” – further innovation and investment are needed (the UK has committed £650M to fusion research)euro-fusion.org.
The Future Impact of Fusion: If these challenges can be overcome, fusion could dramatically reshape energy, climate, and geopolitics. Fusion’s fuel (deuterium, tritium bred from lithium) is essentially limitless and globally available. Unlike fossil fuels, fusion emits no CO₂, and – as EUROfusion observes – its burning of hydrogen isotopes produces “tremendous [heat] energy without any greenhouse contributions,” with “no long-lived waste” and “inherently safe” operation euro-fusion.org. In practical terms, one kilogram of fusion fuel could yield as much energy as millions of kilograms of coal. This means fusion could supply continuous baseload power to complement solar and wind, potentially slashing carbon emissions from power and industry. It could make every country an energy exporter: oil and gas geopolitics would shift if energy was as common as seawater. Analysts say fusion’s promise is hard to overstate. As Reuters reported, CFS claims a future ARC plant could “revolutionize the global energy industry” by tapping a “virtually limitless power source” akin to the stars reuters.com. Indeed, many governments now treat fusion as part of the net-zero strategy – even as they temper expectations about timing.
Outlook: Nuclear fusion is not a short-term fix for the climate emergency. As one Guardian article notes, scientists have “warned that the technology is far from ready to turn into viable power plants” theguardian.com. No one expects fusion to power the grid this decade. But a clear shift has occurred: after decades of funding stalls, fusion is now backed by major governments (US, EU, China, UK budgets are increasing weforum.org), international cooperation (ITER, STEP, etc.), and a surge of private investment. Leading fusion researchers agree that success will require global collaboration: as LLNL’s Kim Budil said, “public-private partnerships” are essential weforum.org.
For the public, the key takeaway is that fusion energy is a race – a high-risk, high-reward quest. The recent breakthroughs show the laws of physics work, but building a useful fusion power plant is an engineering marathon. If it succeeds, however, the payoff could be nothing short of the clean energy revolution: a future where the power of the Sun is harnessed on Earth, fueling our cities and industries with minimal climate impact.
Sources: Authoritative fusion research organizations, news outlets, and scientific publications were consulted. Key recent milestones and expert quotes are drawn from sources including the World Economic Forum weforum.org, World Nuclear News world-nuclear-news.org, international fusion project reports euro-fusion.org, Reuters reuters.com, and U.S. Department of Energy/LLNL publications lasers.llnl.gov. These provide the factual basis for the above overview of fusion science, history, and prospects.
