Over the past few years, fusion power has shifted from being the punchline of sci-fi jokes—always a decade away—to a promising, increasingly achievable technology that’s attracting serious investor interest. While it remains complex and costly to develop today, fusion offers the tantalizing possibility of harnessing the same nuclear reaction that powers the sun to generate virtually limitless clean energy right here on Earth. If startups succeed in building commercially viable fusion power plants, they could disrupt trillion-dollar energy markets and revolutionize global power generation.
This surge of optimism in the fusion industry is fueled by three key technological breakthroughs: more powerful computer chips, advanced artificial intelligence, and high-temperature superconducting magnets. These innovations enable the design of more sophisticated reactors, improve simulation accuracy, and enhance control systems, bringing fusion closer to reality.
A major milestone came at the end of 2022 when a U.S. Department of Energy lab announced it achieved controlled fusion that produced more energy than the lasers delivered to initiate the reaction—a moment known as crossing scientific breakeven. While still a long way from the ultimate goal of commercial breakeven—where the reaction produces more energy than the entire plant consumes—this breakthrough confirmed the science is sound and energized private sector efforts to accelerate development.
Leading the charge are ambitious startups pushing the boundaries of fusion technology:
**Commonwealth Fusion Systems**
In 2021, Commonwealth Fusion Systems (CFS) secured a $1.8 billion Series B funding round, positioning itself as a front-runner. Based in Massachusetts, CFS is building Sparc, a groundbreaking power plant designed to generate power at “commercially relevant” levels. Its reactor employs a tokamak design—shaped like a doughnut—using high-temperature superconducting magnets to contain and compress superheated plasma. In its next phase, called Arc, the company plans to convert the heat from fusion into steam to drive turbines. Collaborating with MIT, CFS aims to have Arc operational by the early 2030s, backed by investors like Breakthrough Energy Ventures, Bill Gates, and The Engine.
**TAE Technologies**
Founded in 1998, TAE Technologies (formerly Tri Alpha Energy) is leveraging a unique approach called field-reversed configuration, enhanced by particle beams that keep the plasma spinning stably. This method extends the fusion reaction’s duration, increasing energy output. With over $1.7 billion raised, TAE continues to innovate from its California base, aiming to make fusion a viable energy source in the coming decades.
**Helion Energy**
Helion, based in Everett, Washington, has an aggressive timeline: it plans to produce electricity from its fusion reactor by 2028, with Microsoft as its first customer. Using a field-reversed configuration similar to others but with its own twist, Helion spins plasma at over a million miles per hour to induce fusion. The company raised over $1 billion, including $425 million in early 2025, coinciding with the startup turning on its prototype reactor, Polaris.
**Pacific Fusion**
Led by renowned scientist Eric Lander, Pacific Fusion burst onto the scene with a massive $900 million Series A. Instead of lasers, this startup uses electromagnetic pulses to compress fuel—an approach called inertial confinement fusion. Its innovative timing ensures all pulses converge precisely to trigger fusion. Funding is tied to achieving specific milestones, a common strategy in biotech, with plans to demonstrate a working reactor in the near future.
**Shine Technologies**
Taking a cautious approach, Shine Technologies focuses on neutron testing, medical isotopes, and radioactive waste recycling. While they aren’t building reactors yet, they’re developing the essential skills needed for future fusion power. With nearly $780 million raised, Shine aims to stay at the forefront of fusion-related innovations.
**General Fusion**
Based in Canada, General Fusion has been working on magnetized target fusion for over two decades. Their approach involves compressing plasma with pistons inside a liquid metal chamber, generating heat to produce steam and electricity. After raising over $440 million, the company faced funding challenges in 2025 but remains committed to bringing its technology to market.
**Tokamak Energy**
This UK-based startup is refining the traditional tokamak design by making it more compact and cost-effective using advanced superconducting magnets. Its prototype, ST40, achieved a plasma temperature of 100 million degrees Celsius, and the company is developing the next-generation Demo 4 reactor to test its systems in real-world scenarios. With over $330 million raised, Tokamak Energy continues to push the boundaries of fusion technology.
**Zap Energy**
In Everett, Washington, Zap Energy is experimenting with a different approach—using electric currents to generate magnetic fields that confine plasma, bypassing the need for superconducting magnets or lasers. Having raised over $320 million, Zap Energy aims to develop a simpler, more scalable fusion reactor.
**Proxima Fusion**
Challenging the norm, Proxima Fusion is developing stellarator technology—twisting and shaping magnetic fields to confine plasma more stably. With over €185 million raised, including a €130 million Series A, the company aims to capitalize on the inherent stability of stellarators, potentially offering a more reliable path to fusion.
**Marvel Fusion**
Based in Munich, Marvel Fusion adopts inertial confinement, similar to the approach used in historic experiments. Using silicon nanostructures, they aim to create more manufacturable and scalable fusion targets. Their collaboration with Colorado State University is set to establish a demonstration facility by 2027, supported by over $160 million in funding.
**First Light**
Originally pursuing fusion energy, First Light shifted gears in 2025 to become a technology provider for other fusion companies. With $140 million raised, they focus on developing tools and components to accelerate fusion research worldwide.
**Xcimer**
Founded in 2022, Xcimer aims to build a more powerful laser system—five times stronger than the National Ignition Facility’s—using molten salt walls to protect reaction chambers from heat damage. With over $100 million raised, the Colorado-based startup is targeting a significant leap in inertial confinement technology.
The fusion industry is rapidly evolving, driven by groundbreaking science and innovative engineering. While commercial fusion is still on the horizon, these pioneering companies are proving that the dream of limitless, clean energy is becoming more attainable every day.
