At CES 2026 on Tuesday, Commonwealth Fusion Systems (CFS) announced the installation of the initial magnet within its Sparc fusion reactor, a prototype scheduled for activation next year.
This magnet is one of 18 planned for the reactor. Once fully assembled, these magnets will form a toroidal structure designed to generate an intense magnetic field, essential for containing and compressing ultra-hot plasma. The goal is for this plasma to yield a net energy gain, producing more energy than consumed in its heating and compression.
Following prolonged periods of anticipation and setbacks, fusion power now seems imminent. CFS and rival companies are vigorously competing to be the first to supply fusion-generated electricity to the grid by the early 2030s. Should it succeed, fusion power promises a virtually infinite source of clean energy, delivered in a format similar to conventional power stations.
Bob Mumgaard, co-founder and CEO of CFS, stated that essential parts for Sparc’s magnets are finished, with all 18 magnets projected for installation by late summer. He anticipates a rapid assembly process for this groundbreaking technology during the first half of the year.
Once positioned, these D-shaped magnets will be mounted vertically on a 24-foot wide, 75-ton stainless steel cryostat, which was installed last March. Each magnet weighs approximately 24 tons and is capable of producing a 20 tesla magnetic field, a strength about 13 times greater than a standard MRI machine. Mumgaard likened their power to being able to ‘lift an aircraft carrier.’
Achieving such immense strength necessitates cooling the magnets to -253˚ C (-423˚ F) to enable them to safely conduct over 30,000 amps of current. Concurrently, within the toroidal chamber, plasma will reach temperatures exceeding 100 million degrees C.
To address potential issues prior to Sparc’s activation, CFS announced Tuesday a collaboration with Nvidia and Siemens to construct a digital twin of the reactor. Siemens will provide the necessary design and manufacturing software, facilitating data collection for integration into Nvidia’s Omniverse libraries.
While CFS has previously conducted extensive simulations to forecast the performance of individual reactor components, Mumgaard explained that these provided isolated results. He noted that with the digital twin, “these are no longer isolated simulations that are just used for design. They’ll be alongside the physical thing the whole way through, and we’ll be constantly comparing them to each other.”
The aspiration is for CFS to conduct experiments and adjust parameters within the digital twin before implementing them on the actual Sparc reactor. He affirmed, “It will run alongside so we can learn from the machine even faster.”
The construction of Sparc represents a significant financial undertaking. To date, CFS has secured almost $3 billion in funding, including an $863 million Series B2 round in August with contributions from Nvidia, Google, and nearly three dozen other investors. The company projects its initial commercial-scale power plant, Arc, a pioneering facility, will require several additional billion dollars in investment.
Mumgaard expressed optimism that the integration of digital twins and AI technology will accelerate the deployment of fusion power to the grid. He commented, “As the machine learning tools get better, as the representations get more precise, we can see it go even faster, which is good because we have an urgency for fusion to get to the grid.”
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