German startup Proxima Fusion has revealed a new fusion reactor design, ‘Stellaris’, which it claims is the fastest route to commercially viable fusion power.
What Is Fusion Energy?
Nuclear fusion, the reaction that powers the sun, occurs when two atomic nuclei combine to form a heavier nucleus, releasing vast amounts of energy. Unlike nuclear fission (the process currently used in our nuclear power stations) which splits atoms and produces long-lived radioactive waste, fusion generates minimal radiation, no carbon emissions, and uses abundant fuel sources like hydrogen isotopes. Scientists have pursued fusion energy for decades due to its potential to provide safe, sustainable, and virtually limitless power.
Who Is Proxima Fusion?
Proxima Fusion, founded in 2023, is the first spin-out from the Max Planck Institute for Plasma Physics (IPP) in Germany. The company has assembled a team of engineers from MIT, Google, SpaceX, and McLaren, all dedicated to overcoming the long-standing technical barriers of fusion power. Their goal is to develop the world’s first commercial fusion power plant, using an innovative stellarator design that builds on decades of plasma physics research.
What Makes the Stellaris Reactor Different?
The new reactor from Proxima Fusion, dubbed ‘Stellaris’, is a quasi-isodynamic (QI) stellarator that utilises high-temperature superconducting (HTS) magnets to create twisted magnetic fields capable of confining hot plasma, a critical step for achieving fusion. Unlike the more widely used tokamak design (such as the one being developed by the ITER project in France), stellarators are inherently stable and can operate continuously. While traditional stellarators have been extremely complex to design and build, advances in AI and computational modelling have allowed Proxima to optimise its approach, making the construction process faster and more cost-effective.
The concept is based on the Wendelstein 7-X, the world’s most advanced stellarator experiment, built at IPP. While Wendelstein 7-X was designed purely for research, Stellaris is engineered to deliver electricity to the grid. Proxima’s first demonstrator, called Alpha, aims to prove net energy production is possible in a steady state and is expected to be completed within six years.
Why This Could Be a Game-Changer
Stellarators have long been overlooked in favour of tokamaks, primarily due to their complexity. However, Proxima Fusion’s approach leverages modern computing power to refine their design, solving problems that were previously insurmountable. AI-driven optimisation allows the company to create reactors that generate more power per unit volume, reduce operational costs, and minimise reliance on scarce materials.
According to Proxima Fusion CEO Francesco Sciortino, “Stellaris is designed to operate in continuous mode and be intrinsically stable. No other fusion power plant design has yet been demonstrated to be capable of that.”
The use of HTS magnets is another key breakthrough. These allow for much stronger magnetic fields than conventional superconductors, meaning the reactor can be significantly smaller and built faster while still achieving the necessary conditions for fusion. Also, Stellaris only relies on materials that are already available in today’s supply chains, making its construction more feasible than previous designs.
The Road to Commercial Fusion
Proxima Fusion has set an ambitious timeline, with the construction of Alpha planned for completion by 2031. If all goes to plan, Stellaris will be the first stellarator to demonstrate sustained net energy production, a milestone never before achieved in fusion research. If successful, the company aims to develop a full-scale 1GW fusion power plant in the 2030s, potentially providing clean, continuous energy to the grid.
Investment
The company’s approach has already attracted significant investment, securing €20 million in funding to accelerate development.
How It Could Change The Energy Sector
If Stellaris lives up to its promise, it could reshape the energy market. Fusion power offers a carbon-free alternative to fossil fuels without the intermittency of renewables like wind and solar. For businesses, this could mean access to a reliable, cost-effective, and sustainable energy source, reducing dependence on volatile energy markets and fossil fuel imports.
From an environmental perspective, widespread adoption of fusion power would mark a major step towards reducing greenhouse gas emissions and mitigating climate change. As global energy demand continues to rise, scalable fusion technology could be the key to long-term energy security.
The Challenges Ahead
Despite all the excitement surrounding Stellaris, it’s worth noting that significant hurdles remain. For example, building a real, commercial fusion reactor requires overcoming immense engineering challenges, including handling the extreme temperatures of the plasma and maintaining precise control of the magnetic fields. Also, while stellarators are more stable than tokamaks, they remain complex machines that require further refinement before they can be deployed at scale.
The Model Coil Next Step
It’s understood that Proxima Fusion’s next step is the development of its Stellarator Model Coil (SMC) by 2027, which will validate the HTS magnet technology before Alpha’s construction begins. If these milestones are achieved, Stellaris could mark the beginning of a new era in clean energy, bringing fusion power out of the laboratory and into the real world.
What Does This Mean For Your Organisation?
The development of the Stellaris reactor could be the next (sooner than expected) step towards the long-sought goal of commercially viable fusion energy. Proxima Fusion’s innovative stellarator design, enabled by modern computational power and high-temperature superconducting magnets, offers a promising alternative to the dominant tokamak approach. By overcoming traditional limitations associated with stellarators, such as complexity and construction feasibility, the company has positioned itself at the forefront of the fusion race.
However, while the technological advances underpinning Stellaris are impressive, the path to commercial deployment remains fraught with challenges. The physics of sustaining controlled fusion at an energy-positive level is well understood, but engineering a reactor that can reliably operate over long periods while remaining economically viable is another matter entirely. The development of the Stellarator Model Coil by 2027 will be a crucial test of Proxima Fusion’s approach, and its success will determine whether the company can proceed with constructing its Alpha prototype as planned.
If Proxima Fusion succeeds in delivering on its ambitious timeline, Stellaris could be a transformative force in the energy sector. A working fusion reactor that can continuously produce clean energy would mark a monumental shift away from fossil fuels and intermittent renewables, offering a sustainable solution to the world’s growing energy needs. However, the history of fusion research is already littered with promising breakthroughs that have struggled to translate into commercial reality. While Proxima Fusion’s advancements are significant, it remains to be seen whether they will be sufficient to surmount the remaining engineering and financial obstacles.
Stellaris, therefore, appears to embody both the potential and the uncertainty of fusion power. For example, if successful, it could usher in a new era of limitless, carbon-free energy. However, like all fusion endeavours, it must first prove that it can move beyond the laboratory and into the real world, which is a major challenge that has eluded every fusion project to date.
