Commonwealth Fusion Systems (CFS) announced at CES 2026 the installation of the first magnet in its Sparc fusion reactor, a crucial step towards turning on the demonstration device next year. This is the initial component of 18 such magnets that, once fully assembled, will form a doughnut-like structure designed to create an extraordinarily powerful magnetic field. This field is essential for confining and compressing superheated plasma, with the ultimate goal of achieving fusion power that releases more energy than it consumes for heating and compression.

Fusion power represents a monumental leap towards nearly limitless clean energy, packaged in a format akin to a traditional power plant. CFS, alongside its competitors, is in an intense race to deliver the first electrons to the grid in the early 2030s. Bob Mumgaard, CFS’ co-founder and CEO, stated that all 18 magnets are anticipated to be installed by the end of the summer, with installations occurring rapidly throughout the first half of the year.

Each D-shaped magnet is a technological marvel, weighing approximately 24 tons and capable of generating a 20 tesla magnetic field, which is about 13 times stronger than a typical MRI machine. Mumgaard likened its strength to being able to lift an aircraft carrier. These magnets will be cooled to an extreme -253˚ C (-423˚ F) to enable them to safely conduct over 30,000 amps of current. They will be positioned upright on a 24-foot wide, 75-ton stainless steel cryostat, which was put in place the previous March. Inside the reactor's doughnut, plasma will reach temperatures exceeding 100 million degrees C.

To meticulously work out any potential issues before Sparc becomes operational, CFS revealed its collaboration with Nvidia and Siemens to develop a comprehensive digital twin of the reactor. Siemens is contributing design and manufacturing software, facilitating data collection that will be fed into Nvidia’s Omniverse libraries. While CFS has already conducted numerous simulations to predict the performance of various reactor parts, these previous efforts provided isolated results. The new digital twin, Mumgaard explained, transcends isolated design simulations, serving as a continuous parallel to the physical machine for constant comparison and learning.

This advanced digital twin will enable CFS to run experiments and tweak parameters virtually before implementing them on the physical Sparc reactor, accelerating the learning process. Building Sparc has been a substantial financial undertaking, with CFS having raised nearly $3 billion to date, including an $863 million Series B2 round in August with investments from Nvidia, Google, and many other investors. The company's subsequent commercial-scale power plant, Arc, is projected to cost several more billions. Mumgaard expressed hope that digital twins and AI technology will significantly expedite the delivery of fusion power to the grid, emphasizing the urgent need for this clean energy solution.