Fusion power — the process that powers the sun and the stars — has been the punchline of energy policy for decades. The joke, popularised in the 1970s, is that fusion is always “30 years away and always will be.” And for most of those decades, the joke was fair. But something has changed. In the last five years, fusion has attracted over $7 billion in private investment, achieved a major scientific milestone and accelerated toward engineering reality. The timeline for commercial fusion power may finally be measured in years rather than generations — though substantial challenges remain.
The Fundamental Attraction
Fusion releases energy by combining light atomic nuclei — typically hydrogen isotopes — into heavier ones, releasing enormous amounts of energy in the process. Unlike nuclear fission, which splits heavy atoms and produces long-lived radioactive waste, fusion produces no long-lived radioactive waste, has no risk of runaway meltdown and uses fuel that is abundant: deuterium can be extracted from seawater, and tritium can be bred from lithium. A single glass of water could, in theory, provide fusion fuel equivalent to the energy of a barrel of oil. The physics is sound — the sun proves it works. The engineering challenge is making it work on Earth.
The challenge is that fusion requires temperatures of over 100 million degrees Celsius — hotter than the core of the sun — to overcome the electrostatic repulsion between atomic nuclei. At those temperatures, matter becomes plasma, a charged gas that must be confined and controlled. The two main approaches are magnetic confinement, using powerful magnets to hold the plasma in a donut-shaped reactor called a tokamak, and inertial confinement, using lasers to compress a fuel pellet to extreme densities and temperatures.
The Breakthrough
In December 2022, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory achieved a historic first: ignition, or scientific breakeven. The facility’s 192 lasers delivered 2.05 megajoules of energy to a fuel pellet, and the resulting fusion reaction released 3.15 megajoules — a gain of about 1.5. It was the first time any fusion experiment had produced more energy from the reaction than was delivered to the fuel. Subsequent experiments have improved on this, with the highest yield reaching over 5 megajoules. This achievement, while a genuine scientific milestone, is not the same as commercial viability: NIF’s lasers require roughly 300 megajoules of electricity to fire, so the facility operates at a net energy loss of about 99%. But it proved that ignition is achievable — a necessary condition for any future power plant.
Private Investment and the Race to Commercialisation
The private fusion sector has been transformed. Commonwealth Fusion Systems, an MIT spin-out using high-temperature superconducting magnets to build a compact tokamak called SPARC, has raised over $2 billion from investors including Bill Gates, Google and Eni. Its SPARC reactor, under construction in Devens, Massachusetts, is designed to demonstrate net energy gain in the mid-2020s. Helion Energy, backed by Sam Altman, claims its approach can achieve commercial fusion by the end of the decade; it has signed a power purchase agreement with Microsoft to supply 50 megawatts of fusion power starting in 2028 — though critics question whether that timeline is realistic. TAE Technologies has raised over $1.2 billion for its beam-driven field-reversed configuration approach. General Fusion, a Canadian company, uses a liquid metal liner and mechanical compression. CFusion has signed agreements with CERN and other research institutions.
Governments are also moving. The ITER project in France, the world’s largest fusion experiment, is a $22 billion international collaboration that aims to demonstrate burning plasma at scale. ITER’s schedule has slipped repeatedly — the first plasma was originally planned for 2020 and is now expected in 2034, with full-power deuterium-tritium operation not until 2039. China has its own program, EAST, which set a record in 2023 for the longest plasma confinement time, and is building a new tokamak, BEST, with a target of 2027. The UK’s STEP program aims for a prototype fusion plant by 2040. The fusion industry is not yet a commercial reality, and the challenges — tritium breeding, materials that survive neutron bombardment, plasma control at scale — are formidable. But for the first time in decades, the “30 years away” joke looks like it may be wrong — or at least, outdated.
