In recent years, the pursuit of fusion energy has transitioned from a distant aspiration to a tangible objective, attracting substantial investments from both private and public sectors. Fusion energy, which replicates the nuclear reactions powering the sun, promises a virtually limitless and clean energy source. This article delves into several pioneering startups that have each secured over $100 million in funding, highlighting their unique approaches and progress in the fusion energy sector.
Commonwealth Fusion Systems (CFS)
Established in 2018 as a spin-off from the Massachusetts Institute of Technology (MIT), Commonwealth Fusion Systems has rapidly emerged as a leader in the fusion energy landscape. In 2021, CFS secured a monumental Series B funding round exceeding $1.8 billion, propelling its total funding to approximately $2 billion. The company’s flagship project, the Sparc reactor, employs a tokamak design—a doughnut-shaped configuration—integrated with high-temperature superconducting magnets. These advanced magnets generate powerful magnetic fields to confine and compress superheated plasma, a critical step toward achieving sustained fusion reactions. CFS anticipates that its commercial-scale reactor, Arc, will be operational in the early 2030s, marking a significant milestone in the commercialization of fusion energy. ([en.wikipedia.org](https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems?utm_source=openai))
TAE Technologies
Founded in 1998 and formerly known as Tri Alpha Energy, TAE Technologies has been at the forefront of fusion research for over two decades. The company has developed a unique approach utilizing a field-reversed configuration (FRC) reactor. In this design, two plasma shots collide in the reactor’s center, forming a spinning cigar-shaped plasma. To maintain stability and prolong the fusion process, TAE employs particle beams that continuously bombard the plasma, enhancing its stability and allowing more time for fusion to occur. This method aims to extract more heat to drive turbines efficiently. As of 2022, TAE Technologies has raised approximately $1.2 billion, with notable investors including Alphabet, Chevron Technology Ventures, and Venrock. ([en.wikipedia.org](https://en.wikipedia.org/wiki/TAE_Technologies?utm_source=openai))
Helion Energy
Based in Everett, Washington, Helion Energy is pioneering a magneto-inertial fusion technology designed to produce helium-3 and fusion power through aneutronic fusion reactions. This approach aims to generate low-cost, clean electric energy using fuel derived exclusively from water. Helion’s reactor employs a field-reversed configuration, where magnets surround an hourglass-shaped reaction chamber. Plasma is spun into doughnut shapes at each end of the chamber and then accelerated toward the center at velocities exceeding one million miles per hour. Upon collision, additional magnets induce fusion, boosting the plasma’s magnetic field and generating an electrical current that can be harvested directly. As of late 2021, Helion had raised $500 million in Series E funding, with an additional $1.7 billion in commitments tied to specific milestones. Investors include Sam Altman, CEO of OpenAI, who also serves as Helion’s executive chairman. ([en.wikipedia.org](https://en.wikipedia.org/wiki/Helion_Energy?utm_source=openai))
General Fusion
Headquartered in Canada, General Fusion is developing a magnetized target fusion system that combines aspects of both magnetic and inertial confinement fusion. The company’s approach involves injecting a magnetized plasma into a liquid metal cavity, which is then compressed to achieve the conditions necessary for fusion. In November 2021, General Fusion completed an oversubscribed Series E funding round, raising over $130 million. Investors included Jeff Bezos, the Business Development Bank of Canada, and hedge fund Segra Capital Management. The funds are dedicated to building a commercial reactor, with the company aiming to demonstrate a practical fusion energy solution in the near future. ([en.wikipedia.org](https://en.wikipedia.org/wiki/General_Fusion?utm_source=openai))
Xcimer Energy
A relative newcomer in the fusion energy sector, Xcimer Energy has made significant strides with its innovative approach. The company focuses on laser-driven inertial fusion, utilizing high-power krypton fluoride (KrF) lasers to achieve fusion conditions. In 2024, Xcimer raised over $100 million in a Series A funding round led by Hedosophia, with participation from Breakthrough Energy, Lowercarbon Capital, and others. The funding is earmarked for constructing a new prototyping facility and developing the Phoenix laser system, which aims to enhance the efficiency and performance of high-power lasers in fusion applications. In February 2025, Xcimer secured an additional $4 million from the Advanced Research Projects Agency-Energy (ARPA-E) to further advance its laser technology. ([en.wikipedia.org](https://en.wikipedia.org/wiki/Xcimer_Energy_Inc.?utm_source=openai))
Avalanche Energy
Avalanche Energy is developing modular fusion reactors designed to provide off-grid energy solutions. The company’s approach involves creating small, desk-sized reactors capable of generating 5 kilowatts of power. In April 2025, Avalanche announced plans to raise up to $100 million in a Series B funding round to support the development of its fusion technology. The company has also opened a commercial test facility in Washington State, aiming to generate revenue while pursuing its long-term goal of commercializing fusion energy. ([axios.com](https://www.axios.com/newsletters/axios-generate-6cad68b0-161a-11f0-9413-e103917bc3de?utm_source=openai))
Pacific Fusion
Pacific Fusion, based in Fremont, California, has adopted a modular approach to fusion energy, which could facilitate the transition from scientific research to commercial-scale reality. In October 2024, the company raised over $900 million in Series A commitments led by General Catalyst. The funding includes less than $100 million in upfront capital, with the remainder contingent on predefined milestones. Pacific Fusion is led by geneticist and mathematician Eric Lander, who previously served as President Biden’s science adviser. The company’s modular design aims to simplify the construction and operation of fusion reactors, potentially accelerating the deployment of fusion energy solutions. ([axios.com](https://www.axios.com/newsletters/axios-pro-rata-03d9ad43-9475-45d1-9c41-dfea03378a54?utm_source=openai))
Conclusion
The substantial investments in these fusion energy startups underscore a growing confidence in the potential of fusion as a viable and sustainable energy source. Each company brings a unique approach to the challenge, from advanced magnetic confinement systems to innovative laser-driven methods. As these startups continue to develop and refine their technologies, the dream of harnessing fusion energy moves closer to reality, promising a future of abundant and clean power.
