Nuclear fusion has moved from distant promise to a series of measurable milestones that are reshaping expectations for clean, abundant energy. In the last few years, record-setting experiments, a new generation of high-field magnets, and the rise of venture-backed fusion firms have changed both the pace and character of progress. Large public projects like ITER are creating the tools and infrastructure for burning-plasma science, while national facilities and private companies are converting physics insights into engineering blueprints. The result is a coordinated, if uneven, march toward machines that could tap deuterium and lithium to produce heat without carbon emissions and with minimal long-lived waste. It is not yet electricity on the grid, but it is a credible, accelerating pathway that deserves attention.
The relevance of these breakthroughs is immediate for a world seeking reliable, low-carbon power at massive scale. Electricity demand is rising as transport, heating, and industry electrify, yet firm capacity that complements wind and solar remains scarce. Fusion promises heat on demand, fuelled by isotopes that are abundant on Earth and not subject to geopolitical bottlenecks. If realized, it could underpin deep decarbonization of steel, chemicals, and shipping, where high-temperature heat is indispensable.
That prospect alone makes today’s experimental progress a meaningful development in the broader energy transition. Recent experiments have delivered clear, verifiable steps forward. At Lawrence Livermore National Laboratory’s National Ignition Facility, a December 2022 shot produced more fusion energy than the laser energy delivered to the fuel capsule, and subsequent shots in 2023 reproduced ignition. In early 2024, the Joint European Torus in the UK set a new world record by releasing 69 megajoules of fusion energy over a few seconds in deuterium-tritium operation, demonstrating sustained performance in a tokamak configuration.
Japan’s superconducting tokamak JT-60SA achieved first plasma in 2023, opening a new platform for studying high-performance regimes relevant to ITER. The Wendelstein 7-X stellarator in Germany has meanwhile delivered long-pulse, well-confined plasmas, sharpening the case for steady-state stellarator approaches. ITER sits at the center of the public fusion landscape, and its scale explains both its promise and its delays. Located in southern France and built by a 35-nation consortium, ITER is designed to produce 500 megawatts of fusion power from 50 megawatts of external heating, a tenfold energy gain in the plasma.
It will not generate electricity, but it will test tritium breeding, heat extraction, and control of a burning plasma at reactor-relevant conditions. The project has acknowledged cost increases and schedule slippage due to component defects, supply-chain disruptions, and the sheer complexity of assembling the world’s largest superconducting magnetic system. Even so, the industrial capacity, metrology, and safety culture being built around ITER are assets the whole sector will draw upon. The private sector has changed the tempo by translating physics into buildable machines and taking on engineering risk.
In 2021, Commonwealth Fusion Systems demonstrated a high-temperature superconducting magnet capable of 20 tesla peak field, enabling more compact tokamaks; its SPARC device is now under construction. Tokamak Energy’s ST40 reached the 100-million-degree threshold in 2022, a temperature regime required for deuterium-tritium fusion, and is advancing high-temperature superconducting magnet technology. Helion Energy signed a power purchase agreement with Microsoft in 2023 for up to 50 megawatts, anchoring a commercial milestone even as the company iterates its pulsed magneto-inertial approach. First Light Fusion has shown fusion from projectile-driven compression, while General Fusion, TAE Technologies, and Zap Energy are pursuing magnetized target, beam-driven field-reversed configuration, and sheared-flow Z-pinch concepts respectively, broadening the technical portfolio.
Capital and policy have followed. Private investment has climbed into the multi-billion-dollar range globally, providing runway for multiple designs to cross key technical gates. In 2023, the U.S. Department of Energy launched a milestone-based fusion development program to co-fund teams working toward a pilot-scale demonstration, tying public dollars to transparent technical deliverables.
The United Kingdom selected West Burton as the site for its STEP prototype plant and is shaping a regulatory pathway tailored to fusion’s hazard profile. The U.S. Nuclear Regulatory Commission decided in 2023 to regulate fusion under the byproduct material framework rather than fission’s power reactor rules, while European and Japanese programs continue long-term public research under EUROfusion and broader international cooperation. The notion of “unlimited” energy rests on well-understood fuel fundamentals, but it still must pass through hard engineering gates.
Deuterium exists in seawater at levels sufficient for power production far beyond human timescales, and lithium can be used in breeding blankets to create tritium inside a reactor. Turning that into a plant requires materials that survive intense neutron bombardment, blankets that efficiently breed and extract tritium, and divertors that handle heat loads greater than those on a spacecraft reentry. High-temperature superconducting tapes must scale in volume and cost, and precision manufacturing of vacuum vessels, cryostats, and microwave systems must mature. None of these hurdles is insurmountable in principle, but each demands sustained, multi-disciplinary engineering.
A clear-eyed assessment also distinguishes between physics breakeven and practical power production. NIF’s ignition is a major scientific accomplishment in inertial confinement, yet the overall system remains far from net electrical gain because the laser system consumes far more grid power than the energy delivered to the target. Magnetic fusion devices like tokamaks and stellarators pursue continuous operation, but they must demonstrate high gain with steady-state control, efficient current drive where needed, and long component lifetimes. Even after a device closes an energy balance at the plant level, it must compete on cost, reliability, and maintainability against an increasingly inexpensive mix of renewables, storage, and advanced fission.
That is why much of today’s work focuses on engineering integration and cost-informed design, not just plasma performance. If fusion clears those thresholds, its system value could be distinctive. A fusion plant would offer high-capacity-factor, dispatchable heat and power with no direct carbon emissions and without long-lived, high-level waste, easing siting and public acceptance relative to fission in many jurisdictions. It could anchor industrial hubs producing green hydrogen, sustainable aviation fuels, and process heat, and provide stable electricity that reduces the amount of storage and transmission needed for a renewable-heavy grid.
Fuel logistics are modest, land footprints are compact, and safety scenarios are bounded by low fuel inventories and self-limiting plasma physics. These attributes would complement wind, solar, hydro, and geothermal rather than replace them. The story unfolding is not one of a single breakthrough but of compounding progress across science, engineering, policy, and markets. Record shots at national laboratories validate the physics; ITER and JT-60SA are building the operating knowledge for burning plasmas; private firms are compressing development cycles and testing manufacturability.
Knowledge spillovers—from superconductors and power electronics to advanced manufacturing, lasers, and materials science—are strengthening adjacent clean technologies. Over the next decade, the most credible signals will be transparent milestones: first-plasma achievements, sustained high-gain discharges, component lifetime demonstrations, and, ultimately, pilot plants that put electricity onto a meter. On that path, fusion’s promise of effectively inexhaustible, clean energy can move from aspiration to infrastructure.