every fusion startup that has raised over $100m

The Rising Potential of Fusion Power

For many years, fusion power was often dismissed as an unattainable goal – perpetually “ten years away.” However, in recent times, it has transitioned into a remarkably promising and realistic technology, attracting significant investment.

While mastering this technology and constructing fusion power plants presents considerable challenges and costs, the potential benefits are immense. Fusion aims to replicate the nuclear reactions occurring within the sun, offering the prospect of generating virtually limitless energy on Earth.

Key Drivers of Progress

The recent surge in optimism surrounding the fusion industry can be attributed to three pivotal advancements. These include the development of more potent computer chips, increasingly sophisticated artificial intelligence, and the creation of powerful high-temperature superconducting magnets.

These innovations have collectively facilitated the design of more advanced reactors, improved simulation capabilities, and the implementation of more intricate control systems.

A Landmark Achievement

A significant milestone was reached in late 2022 when a U.S. Department of Energy laboratory announced a successful controlled fusion reaction. This experiment generated more power than was initially delivered to the fuel pellet by the lasers.

This achievement, known as scientific breakeven, represents a crucial step forward. Although commercial breakeven – where the reaction’s output exceeds the facility’s total energy consumption – remains a future objective, it validated the fundamental scientific principles behind fusion.

Accelerated Development

Building upon this momentum, entrepreneurs have propelled the private fusion sector forward at an accelerated rate in recent years.

The potential for commercially viable fusion power plants to disrupt multi-trillion dollar energy markets is now a serious consideration for investors and researchers alike.

Here's a summary of the advancements:

• More powerful computer chips enable complex simulations.
• Sophisticated AI optimizes reactor control.
• High-temperature superconducting magnets enhance reactor performance.

Commonwealth Fusion Systems

To date, Commonwealth Fusion Systems (CFS) has secured approximately one-third of all private investment allocated to fusion energy ventures. A recent funding round finalized in August contributed $863 million, elevating the company’s total funding to nearly $3 billion.

The Series B2 funding for CFS arrived four years following a substantial $1.8 billion Series B investment. This earlier funding propelled CFS to a leading position within the industry. Since then, the company has been actively engaged in constructing Sparc in Massachusetts.

Sparc represents CFS’s pioneering power plant, designed to generate electricity at levels considered “commercially viable.” The reactor utilizes a tokamak design, characterized by its doughnut-like shape. This structure is encircled by high-temperature superconducting tape.

When energized, this tape creates a robust magnetic field. This field is crucial for containing and compressing the extremely hot plasma within the reactor. The heat produced by the fusion reaction is then harnessed to create steam, which drives a turbine for electricity generation.

Magnet design for CFS was a collaborative effort with MIT. Bob Mumgaard, co-founder and CEO, previously conducted research at MIT focusing on fusion reactor designs and high-temperature superconductors.

CFS anticipates Sparc will be fully operational by late 2026 or early 2027. Following this, the company plans to commence construction on Arc, a commercial power plant, later in the decade.

Arc is projected to generate 400 megawatts of electrical power. The planned location for this facility is near Richmond, Virginia. Notably, Google has committed to purchasing 50% of the electricity produced by Arc.

A diverse group of investors supports CFS, including Breakthrough Energy Ventures, The Engine, Bill Gates, and numerous others.

TAE Technologies: A Fusion Energy Pioneer

Established in 1998, TAE Technologies, initially operating as Tri Alpha Energy, originated as a spin-off from research conducted at the University of California, Irvine. The foundational work was spearheaded by Norman Rostoker.

The company employs a field-reversed configuration approach to fusion. However, TAE introduces a unique element to this method.

Innovative Plasma Control

Following the collision of two plasma streams within the reactor core, TAE implements a technique of injecting particle beams into the plasma. This bombardment maintains the plasma’s elongated, cigar-like form.

Maintaining this shape is crucial. It significantly enhances plasma stability, extending the duration of the fusion process and maximizing heat extraction for turbine operation.

Recent Funding and Investment

In June, TAE Technologies secured an additional $150 million in funding from its current investor base. This group includes prominent entities such as Google, Chevron, and New Enterprise.

To date, TAE Technologies has accumulated a total of $1.79 billion in funding, as reported by PitchBook.

Key investors demonstrate confidence in TAE’s approach to achieving viable fusion energy.

Helion

Among all companies working on fusion energy, Helion is distinguished by its particularly ambitious schedule. The organization intends to generate electricity utilizing its reactor by the year 2028.

Microsoft has been identified as the company’s inaugural client.

Reactor Design and Operation

Helion, headquartered in Everett, Washington, employs a reactor design known as a field-reversed configuration. This system utilizes magnets to encircle a reaction chamber.

The chamber’s shape is reminiscent of an hourglass, featuring a widened section where the two halves converge.

At either end of this hourglass structure, plasma is rotated into toroidal forms and accelerated towards each other at velocities exceeding 1 million miles per hour.

Upon collision within the central region, supplementary magnets facilitate the initiation of fusion.

The occurrence of fusion amplifies the plasma’s inherent magnetic field, subsequently inducing an electrical current within the reactor’s magnetic coils.

This generated electricity is then directly extracted from the machine.

Funding and Investment

In January 2025, Helion secured $425 million in funding, coinciding with the activation of Polaris, a prototype reactor.

To date, the company has amassed a total of $1.03 billion in investment, as reported by PitchBook.

Notable investors include:

• Sam Altman
• Reid Hoffman
• KKR
• BlackRock
• Peter Thiel’s Mithril Capital Management
• Capricorn Investment Group

These investments demonstrate significant confidence in Helion’s approach to achieving practical fusion power.

The substantial financial backing allows for continued development and refinement of their reactor technology.

Pacific Fusion

A substantial $900 million Series A funding round has propelled Pacific Fusion into the spotlight, marking a significant investment even within the competitive landscape of fusion energy startups.

The company’s approach to achieving fusion centers on inertial confinement, but diverges from conventional methods. Instead of laser-based compression, Pacific Fusion will employ precisely timed electromagnetic pulses.

Key Technological Aspects

Central to their strategy is the precise synchronization of 156 impedance-matched Marx generators. These generators must collectively deliver 2 terawatts of power for a duration of only 100 nanoseconds.

Successful fusion relies on the simultaneous convergence of these pulses onto the fuel target.

Leadership and Funding Structure

Eric Lander, renowned for his leadership of the Human Genome Project, serves as Pacific Fusion’s CEO, while Will Regan holds the position of president.

Although the funding amount is considerable, it won’t be delivered as a single payment. Instead, investors will release funds in stages as the company successfully meets predetermined milestones.

This phased funding approach, frequently utilized in the biotechnology sector, allows for continuous evaluation and support based on tangible progress.

• Inertial confinement fusion is the core principle guiding Pacific Fusion’s research.
• Electromagnetic pulses represent a novel compression method.
• The success of the project hinges on the precise timing of Marx generators.

Pacific Fusion’s innovative strategy and strong leadership position it as a noteworthy contender in the pursuit of commercially viable fusion energy.

Shine Technologies

Shine Technologies is adopting a measured – and realistically focused – strategy concerning the development of fusion power. Direct sales of electricity produced by a fusion reactor remain a future prospect, therefore the company is initially concentrating on providing neutron testing services and producing medical isotopes.

Furthermore, Shine has recently been engaged in the creation of a method for the reprocessing of radioactive waste materials.

The company has not yet committed to a specific design for a prospective fusion reactor. Instead, it is prioritizing the acquisition of essential expertise in preparation for future advancements in the field.

Funding and Investors

According to data from PitchBook, Shine Technologies has secured a total of $778 million in funding.

Key investors contributing to this funding include Energy Ventures Group, Koch Disruptive Technologies, Nucleation Capital, and the Wisconsin Alumni Research Foundation.

Neutron testing and medical isotope production represent initial revenue streams.

Shine’s strategy emphasizes building core competencies before full-scale power generation.

The company’s financial backing demonstrates confidence in its long-term vision.

General Fusion

Having operated for over two decades, General Fusion has secured $462.53 million in funding, as reported by PitchBook. Established in 2002 in Richmond, British Columbia, the company was initiated by physicist Michel Laberge. His goal was to demonstrate the viability of an alternative fusion method called magnetized target fusion (MTF).

Notable investors in General Fusion include Jeff Bezos, Temasek, BDC Capital, and Chrysalix Venture Capital.

How the Reactor Works

The General Fusion reactor design features a chamber encircled by a liquid metal wall. Plasma is then introduced into this chamber. A series of pistons positioned around the wall are activated, driving it inward. This action compresses the plasma, initiating a fusion reaction.

The fusion process generates neutrons, which subsequently heat the liquid metal. This heated metal is then circulated through a heat exchanger, producing steam that drives a turbine for electricity generation.

Recent Challenges

General Fusion encountered financial difficulties in the spring of 2025. As the company was constructing LM26, its most recent device, a cash shortage emerged. LM26 was intended to achieve breakeven by 2026.

Shortly after reaching a significant milestone, the company was forced to reduce its workforce by 25%. CEO Greg Twinney publicly appealed to investors for additional funding through an open letter.

In August, a funding injection of $22 million was secured in a pay-to-play round. One investor characterized this amount as “the least amount of capital possible” needed to maintain General Fusion’s operations.

Tokamak Energy

Tokamak Energy employs a modified tokamak approach—characterized by its toroidal, or doughnut-shaped, configuration—by compressing it. This compression lowers the aspect ratio, ultimately resulting in a form that approaches a spherical shape.

Similar to numerous other ventures focused on tokamak technology, the company utilizes high-temperature superconducting magnets. These magnets are based on REBCO, or rare earth barium copper oxide materials.

Because of its more condensed design when compared to conventional tokamaks, a reduced quantity of magnets is needed. This should contribute to lower overall expenses.

ST40 and Demo 4 Prototypes

The company’s ST40 prototype, situated in Oxfordshire, U.K., is visually striking, resembling an elaborate, steampunk-inspired Fabergé egg. In 2022, this device successfully produced an extremely hot plasma reaching 100 million degrees Celsius.

Currently, the next-generation reactor, named Demo 4, is being built. Its purpose is to evaluate the company’s magnets under conditions that mirror those found in actual fusion power plants.

Funding and Investment

Tokamak Energy secured $125 million in funding in November 2024. These funds will be allocated to furthering reactor design and expanding the company’s magnet manufacturing capabilities.

To date, the company has accumulated a total of $336 million in investment.

Investors include Future Planet Capital, In-Q-Tel, Midven, and Hans-Peter Wild, the founder of Capri-Sun, as reported by PitchBook.

• Key Technology: High-temperature superconducting magnets (REBCO).
• Prototype Success: 100 million degree C plasma achieved with ST40.
• Future Focus: Testing magnets in power plant-relevant scenarios with Demo 4.

Zap Energy: A Novel Approach to Fusion

Zap Energy employs a unique method for plasma confinement, diverging from the use of high-temperature superconducting magnets or high-powered lasers. Instead, the process relies on applying an electric current directly to the plasma, initiating the creation of its own magnetic field.

This self-generated magnetic field then compresses the plasma to a dimension of approximately 1 millimeter, ultimately leading to the conditions necessary for ignition.

The Fusion Process and Energy Extraction

The fusion reaction releases neutrons, which are directed towards a surrounding liquid metal blanket. This bombardment heats the liquid metal significantly.

Subsequently, the heated liquid metal is circulated through a heat exchanger, generating steam that powers a turbine for electricity production.

Funding and Location

Zap Energy, similar to Helion, is headquartered in Everett, Washington.

The company has successfully secured $327 million in funding, as reported by PitchBook.

• Investors include Breakthrough Energy Ventures (backed by Bill Gates), DCVC, Lowercarbon, Energy Impact Partners, and Chevron Technology Ventures.
• Bill Gates himself has also contributed as an angel investor.

This substantial investment underscores the growing interest in Zap Energy’s innovative fusion technology.

Proxima Fusion

A significant portion of investment within the fusion energy sector has historically been directed towards larger startups focused on either tokamak or inertial confinement approaches.

However, stellarator technology has consistently demonstrated substantial potential through various scientific trials, notably exemplified by the Wendelstein 7-X reactor located in Germany.

Recent Funding

Proxima Fusion is diverging from this established pattern, having successfully secured a €130 million Series A funding round. This brings the company’s total funding to over €185 million.

Key investors participating in this round include Balderton Capital and Cherry Ventures.

Understanding Stellarators

Stellarators share similarities with tokamaks in their method of confining plasma within a toroidal, or ring-shaped, configuration utilizing strong magnetic fields.

A key distinction lies in their design philosophy; stellarators employ intentionally complex, twisted, and bulged shapes.

The Advantage of Complexity

This intricate geometry isn't arbitrary. It’s designed to naturally accommodate the inherent instabilities of plasma.

By adapting to the plasma’s behavior, stellarators aim to achieve prolonged plasma stability, thereby enhancing the probability of successful fusion reactions.

The goal is to maintain the conditions necessary for fusion for extended periods, which is crucial for practical energy generation.

Marvel Fusion: A Novel Approach to Inertial Confinement

Marvel Fusion is pursuing inertial confinement fusion, a method mirroring the successful technique employed by the National Ignition Facility. This facility demonstrated the feasibility of achieving controlled nuclear fusion reactions that generate net energy gain.

The process utilized by Marvel Fusion involves directing high-intensity lasers onto a target containing silicon nanostructures. These structures undergo a cascading effect under laser impact, resulting in the compression of the fuel to ignition conditions.

A key advantage of Marvel Fusion’s design lies in the use of silicon for target fabrication. This material choice should facilitate relatively straightforward manufacturing processes, leveraging the established expertise within the semiconductor industry.

Demonstration Facility and Funding

Currently, the inertial confinement fusion startup is constructing a demonstration facility in partnership with Colorado State University. Operations at this facility are anticipated to commence by the year 2027.

Headquartered in Munich, Marvel Fusion has successfully secured $161 million in funding. Investors include prominent firms such as b2venture, Deutsche Telekom, Earlybird, and HV Capital.

Furthermore, the company has received angel investments from Taavet Hinrikus and Albert Wenger, bolstering its financial foundation for continued development.

• Key Technology: Inertial confinement fusion utilizing silicon nanostructures.
• Target Ignition: Achieved through high-powered laser bombardment.
• Manufacturing: Leverages existing semiconductor manufacturing capabilities.
• Facility Timeline: Operational demonstration facility expected by 2027.
• Total Funding: $161 million secured from various investors.

The company’s approach aims to provide a scalable and economically viable pathway towards realizing the potential of fusion energy.

First Light's Strategic Shift

In March of 2025, First Light discontinued its independent efforts to achieve fusion power.

The company has since redirected its focus towards serving as a technology provider for emerging fusion companies and other organizations within the sector.

Previous Research Approach

First Light had been developing a fusion technology based on inertial confinement.

This method involves compressing pellets of fusion fuel to the point of ignition.

Funding and Investors

According to PitchBook data, First Light has secured $140 million in funding.

Notable investors include Invesco, IP Group, and Tencent.

The company’s headquarters are located in Oxfordshire, U.K.

New Business Model

• First Light will now concentrate on supplying key technologies.
• This includes components and expertise for other fusion startups.
• The shift allows the company to capitalize on the growing fusion energy market.

This strategic change represents a significant evolution for First Light.

It positions the company to play a crucial role in the advancement of fusion energy, even without directly pursuing power generation itself.

Xcimer

While fusion energy presents inherent complexities, Xcimer is pursuing a comparatively direct methodology. The company intends to build upon the foundational scientific principles demonstrated by the National Ignition Facility’s recent achievement of net-positive energy gain.

Xcimer’s strategy involves a complete re-engineering of the technologies utilized in that landmark experiment. This Colorado-based startup is developing a 10-megajoule laser system, which represents a fivefold increase in power compared to the NIF’s historic apparatus.

Key Technological Features

A crucial element of Xcimer’s design incorporates molten salt walls. These walls are positioned to encircle the reaction chamber, effectively capturing heat and shielding the primary solid wall from potential damage.

Established in January 2022, Xcimer has rapidly secured substantial funding. To date, the company has raised $109 million, as reported by PitchBook.

This financial backing comes from a diverse group of investors, including Hedosophia, Breakthrough Energy Ventures, Emerson Collective, Gigascale Capital, and Lowercarbon Capital.

This article initially appeared in September 2024 and will be updated on an ongoing basis.