Commonwealth Fusion has raised $2 billion to make energy like the sun and stars — here’s a look inside
The tokamak room at the Commonwealth Fusion Systems construction site where the tokamak will go that will, company executives tell CNBC, demonstrate net energy, a key milestone in achieving fusion.
Cat Clifford, CNBC
Commonwealth Fusion Systems CEO Bob Mumgaard is a student of the history of technology.
“If you go and you look at what fusion looks like today, you say, ‘Oh this feels kind of like flight in 1918,'” Mumgaard told CNBC in a recent video interview.
In June 1919, two British aviators and war veterans made the first-ever nonstop transatlantic flight, departing from St. John’s, Newfoundland, and landing in County Galway, Ireland. A century later, transatlantic flights are so common, they’re not even noteworthy.
Nuclear fusion is the way stars make energy. A fusion reaction releases more energy than nuclear fission, which is the way nuclear reactors generate power today. Similar to fission, fusion does not release any of the greenhouse gasses that cause global warming. Unlike fission, it also does not generate long-lasting nuclear waste.
For all these reasons, fusion is often called the “Holy Grail” of clean energy.
Research into a device that can replicate and maintain fusion on earth stretches back to the 1950s, but is showing new, if uneven, progress. Scientists at Lawrence Livermore National Lab announced in May they were able to momentarily achieve the key fusion milestone known as ignition, where more power is generated from the reaction than goes into the reaction to get it going, but that was a brief flicker. A fusion power plant has been, so far, firmly rooted in the realm of science fiction.
Commonwealth is trying to change that, and has raised more than $2 billion in venture capital from the likes of Bill Gates, Gates’ climate investment firm Breakthrough Energy Ventures, Google, John Doerr, Khosla Ventures, Lowercarbon Capital, Marc Benioff’s TIME Ventures and more. That’s more private capital than any other fusion startup, according to the Fusion Industry Association, the industry’s trade group.
Last week, Commonwealth announced it was one of the eight companies selected by the U.S. Department of Energy to receive a collective $46 million in funding as it achieved certain preestablished milestones.
So why now?
Mumgaard is used to hearing all the reasons why fusion won’t work.
“The skepticism is understandable,” Mumgaard told CNBC. “That doesn’t bother us. We have to build things and show that they work.”
Historically, humans are slow to change their understanding of technological possibility.
“Everyone has different thresholds for what they have to see to believe something,” Mumgaard said. “When the Wright brothers were flying, you still had skeptics that said planes couldn’t exist.”
But Mumgaard also asks for a bit of optimism and curiosity, too. “You don’t have to believe us today. But you at least have to be interested in watching the story and tracking the story. And it’s a race. We’re at the beginning of a race,” Mumgaard told CNBC.
Bob Mumgaard, CEO, Commonwealth Fusion Systems.
Photo courtesy Commonwealth Fusion Systems
You don’t need to be a nuclear physicist to follow this race. Mumgaard laid out the stages for fusion watchers to look for. First, fusion companies need to make plasma, which is the fourth state of matter after solid, liquid and gas, and is the very fragile condition necessary to maintain a fusion reaction. Then, fusion companies need to make that plasma super hot. Then, that hot plasma has to be confined and protected. In the industry, this trio of conditions — density, temperature and confinement or insulation — is called the “triple product.”
Once fusion companies get that triple product, they then are going to start reaching ignition, after which they will generate an abundance of clean, waste-free energy.
Or so that’s the plan. Right now, that race is “accelerating,” Mumgaard says. “You’re seeing more entrants; you’re seeing entrants get faster and pull away.”
Demand for clean energy, advancements in science and development in the technology of the component parts necessary to make a fusion device are all coming together right now to make this moment the tipping point in the race for fusion, Mumgaard says.
The first factor is the increasingly urgent demand for new sources of energy that do not contribute to climate change.
The Commonwealth Fusion Systems campus is headquartered in Devens, Massachusetts, which is between 35 miles and 40 miles outside of downtown Boston.
Cat Clifford, CNBC
Top climate scientists at the United Nations Intergovernmental Panel on Climate Change have said that to have “no or limited” overshoot of the 1.5 degrees Celsius warming above pre-industrial levels will require hitting net-zero around 2050. Knowing the world needs to go to net-zero global emissions by 2050 is akin to being in the analog age and knowing precisely when the Internet Revolution was going to begin, Mumgaard says.
“The energy transition is the largest market transition in human history,” Mumgaard told CNBC. That’s more than generating electricity. “How we generate power, how we make our chemicals, how we do our steel, how we do our cement — you are taking all of that and you are rebuilding it without carbon.”
Wind and solar energy are already being deployed at scale, but fusion can serve to replace large, baseload energy demands such as powering steel and cement manufacturing, industrial furnaces and urban centers. “That’s a missing hole,” Mumgaard told CNBC. “And it gets more and more acute as you get deeper and deeper into the transition.”
Nuclear fission could be that kind of baseload energy, but as Germany has very recently demonstrated, some populations are against fission because of the waste and risk of nuclear accidents similar to those at Chernobyl and Fukushima.
“We don’t want to limit our options to either force something that people don’t want, or to hope that we convince people of something that they’re dead set against,” Mumgaard told CNBC.
In addition to increased demand, a set of scientific and technological advances are also pushing fusion forward.
“We’ve constantly actually gotten better and better at fusion, even though from the outside, we haven’t passed a big milestone by making a fusion power plant,” Mumgaard told CNBC. “We’ve just accumulated a huge amount of science the same way like we accumulate a huge amount of science about gene sequence, about the genome.”
Large supercomputers are good enough now to simulate what is happening inside fusion devices, and technological developments such as machine learning and fast actuators are being applied to making fusion devices in new ways.
Most critically for Commonwealth, the capacity to build ultrastrong magnets is better now than it ever has been before.
Commonwealth uses those magnets to hold the plasma in place, and five years ago they didn’t exist, Mumgaard told CNBC, because the material used to make them didn’t exist at the quantities necessary.
The advanced manufacturing facility located at the Commonwealth Fusion Systems campus in Devens, Massachusetts, where magnets are manufactured.
Photo courtesy Commonwealth Fusion Systems
That material is a high-temperature superconducting tape. The breakthrough of making high-temperature superconducting material was achieved in the 1980s, and won two physicists the Nobel Prize in 1987 for their discovery. But it took a long time and lots of science before that material could be made outside a lab, Mumgaard says.
What it looks like to spend $2 billion to build a fusion machine
In the race to deliver fusion, Commonwealth is a front-runner.
“Since their founding only five years ago, the growth at Commonwealth Fusion Systems has been groundbreaking. Their growth is not based on speculation or idle promises, but on results,” Andrew Holland, CEO of the Fusion Industry Association, a trade group, told CNBC. “Their leadership role in helping organize the fusion industry has lifted the whole industry toward a vision for commercialization on an aggressive timeline.”
At Commonwealth’s 50-acre headquarters in Devens, Massachusetts, about 40 miles from Boston, chief scientific officer Brandon Sorbom told CNBC the company has a significant procurement team managing the supply chain necessary to build a tokamak, the donut-shaped fusion device at the heart of the company’s system, in addition to an extensive team manufacturing parts on site.
The SPARC facility under construction at the Commonwealth Fusion Systems campus in Devens, Massachusetts.
Cat Clifford, CNBC
Right now, Commonwealth is focused on building its tokamak, called SPARC, with a goal of turning it on in 2025. It will shortly thereafter demonstrate net energy gain, Sorbom told CNBC.
After building SPARC, Commonwealth’s next goal is to build ARC, a more mature version of its fusion device that will deliver electricity to the grid, Sorbom told CNBC. ARC is scheduled to be completed in the early 2030s and will collect the heat generated by the fusion reaction in molten salt and use that heat to turn a turbine generator to make electricity, Sorbom added.
A rendering of the SPARC device Commonwealth Fusion Systems is building to demonstrate net energy.
Cat Clifford, CNBC
Early on, Commonwealth will develop and be partial owner of fusion power plants, Ally Yost, chief of staff, told CNBC, and will make money as other power generators do: by selling electricity.
But eventually, Commonwealth will operate more like Boeing does for the airline industry.
“They are the designers and owners of the IP around the designs of the planes. They are manufacturers of key components.” Commonwealth may also have a service component of its business and customers will likely be utilities, industrial companies or energy-hungry tech companies, Yost told CNBC.
Reporter Cat Clifford in the Commonwealth Fusion Systems tokamak room where the SPARC facility will demonstrate net energy.
Cat Clifford, CNBC
But right now, the focus is getting the demonstration plant, SPARC, turned on.
The facility that will house SPARC has five prongs, and at the center is the room that houses the tokamak, Alex Creely, the head of tokamak operations, told CNBC during a tour of the facility. It will be 25 feet tall and about 25 feet in diameter, and the ARC tokamak is going to be roughly twice as big.
The Commonwealth Fusion Systems’ SPARC facility under construction in Devens, Massachusetts.
Cat Clifford, CNBC
Even though Commonwealth is still only building its first demonstration reactor, Mumgaard sees the dawning of the fusion age as inevitable.
“To know that it is not just scientifically feasible, but industrially feasible and commercially feasible, and that there is momentum to turn that into a product and take that heat and turn it into electricity, that is a big deal,” Mumgaard told CNBC. “Once you know you have that option, how does it change that bigger story on climate?”
Technology
Alibaba-backed Moonshot releases new Kimi AI model that beats ChatGPT, Claude in coding — and it costs less
An AI sign at the MWC Shanghai tech show on June 19, 2025.
Bloomberg | Bloomberg | Getty Images
BEIJING — The latest Chinese generative artificial intelligence model to take on OpenAI’s ChatGPT is offering coding capabilities — at a lower price.
Alibaba-backed startup Moonshot released on late Friday night its Kimi K2 model: a low-cost, open source large language model — the two factors that underpinned China-based DeepSeek’s industry disruption in January. Open-source technology provides source code access for free, an approach that few U.S. tech giants have taken, other than Meta and Google to some extent.
Coincidentally, OpenAI CEO Sam Altman announced early Saturday that there would be an indefinite delay of its first open-source model yet again due to safety concerns. OpenAI did not immediately respond to a CNBC request for comment on Kimi K2.
One of Kimi K2’s strengths is in writing computer code for applications, an area in which businesses see potential to reduce or replace staff with generative AI. OpenAI’s U.S. rival Anthropic focused on coding with its Claude Opus 4 model released in late May.
In its release announcement on social media platforms X and GitHub, Moonshot claimed Kimi K2 surpassed Claude Opus 4 on two benchmarks, and had better overall performance than OpenAI’s coding-focused GPT-4.1 model, based on several industry metrics.
“No doubt [Kimi K2 is] a globally competitive model, and it’s open sourced,” Wei Sun, principal analyst in artificial intelligence at Counterpoint, said in an email Monday.
Cheaper option
“On top of that, it has lower token costs, making it attractive for large-scale or budget-sensitive deployments,” she said.
The new K2 model is available via Kimi’s app and browser interface for free unlike ChatGPT or Claude, which charge monthly subscriptions for their latest AI models.
Kimi is also only charging 15 cents for every 1 million input tokens, and $2.50 per 1 million output tokens, according to its website. Tokens are a way of measuring data for AI model processing.
In contrast, Claude Opus 4 charges 100 times more for input — $15 per million tokens — and 30 times more for output — $75 per million tokens. Meanwhile, for every one million tokens, GPT-4.1 charges $2 for input and $8 for output.
Moonshot AI said on GitHub that developers can use K2 however they wish, with the only requirement that they display “Kimi K2” on the user interface if the commercial product or service has more than 100 million monthly active users, or makes the equivalent of $20 million in monthly revenue.
Hot AI market
Initial reviews of K2 on both English and Chinese social media have largely been positive, although there are some reports of hallucinations, a prevalent issue in generative AI, in which the models make up information.
Still, K2 is “the first model I feel comfortable using in production since Claude 3.5 Sonnet,” Pietro Schirano, founder of startup MagicPath that offers AI tools for design, said in a post on X.
Moonshot has open sourced some of its prior AI models. The company’s chatbot surged in popularity early last year as China’s alternative to ChatGPT, which isn’t officially available in the country. But similar chatbots from ByteDance and Tencent have since crowded the market, while tech giant Baidu has revamped its core search engine with AI tools.
Kimi’s latest AI release comes as investors eye Chinese alternatives to U.S. tech in the global AI competition.
Still, despite the excitement about DeepSeek, the privately-held company has yet to announce a major upgrade to its R1 and V3 model. Meanwhile, Manus AI, a Chinese startup that emerged earlier this year as another DeepSeek-type upstart, has relocated its headquarters to Singapore.
Over in the U.S., OpenAI also has yet to reveal GPT-5.
Work on GPT-5 may be taking up engineering resources, preventing OpenAI from progressing on its open-source model, Counterpoint’s Sun said, adding that it’s challenging to release a powerful open-source model without undermining the competitive advantage of a proprietary model.
Grok 4 competitor
Kimi K2 is not the company’s only recent release. Moonshot launched a Kimi research model last month and claimed it matched Google’s Gemini Deep Research ‘s 26.9 score and beat OpenAI’s version on a benchmark called “Humanity’s Last Exam.”
The Kimi research model even got a mention last week during Elon Musk’s xAI release of Grok 4 — which scored 25.4 on its own on the “Humanity’s Last Exam” benchmark, but attained a 44.4 score when allowed to use a variety of AI tools and web search.
“Kimi-Researcher represents a paradigm shift in agentic AI,” said Winston Ma, adjunct professor at NYU School of Law. He was referring to AI’s capability of simultaneously making several decisions on its own to complete a complex task.
“Instead of merely generating fluent responses, it demonstrates autonomous reasoning at an expert level — the kind of complex cognitive work previously missing from LLMs,” Ma said. He is also author of “The Digital War: How China’s Tech Power Shapes the Future of AI, Blockchain and Cyberspace.”
— CNBC’s Victoria Yeo contributed to this report.
Co-founder and chief executive officer of Nvidia Corp., Jensen Huang attends the 9th edition of the VivaTech trade show in Paris on June 11, 2025.
Chesnot | Getty Images Entertainment | Getty Images
Nvidia CEO Jensen Huang has downplayed U.S. fears that his firm’s chips will aid the Chinese military, days ahead of another trip to the country as he attempts to walk a tightrope between Washington and Beijing.
In an interview with CNN aired Sunday, Huang said “we don’t have to worry about” China’s military using U.S.-made technology because “they simply can’t rely on it.”
“It could be limited at any time; not to mention, there’s plenty of computing capacity in China already,” Huang said. “They don’t need Nvidia’s chips, certainly, or American tech stacks in order to build their military,” he added.
The comments were made in reference to years of bipartisan U.S. policy that placed restrictions on semiconductor companies, prohibiting them from selling their most advanced artificial intelligence chips to clients in China.
Huang also repeated past criticisms of the policies, arguing that the tactic of export controls has been counterproductive to the ultimate goal of U.S. tech leadership.
“We want the American tech stack to be the global standard … in order for us to do that, we have to be in search of all the AI developers in the world,” Huang said, adding that half of the world’s AI developers are in China.
That means for America to be an AI leader, U.S. technology has to be available to all markets, including China, he added.
Washington’s latest restrictions on Nvidia’s sales to China were implemented in April and are expected to result in billions in losses for the company. In May, Huang said chip restrictions had already cut Nvidia’s China market share nearly in half.
Huang’s CNN interview came just days before he travels to China for his second trip to the country this year, and as Nvidia is reportedly working on another chip that is compliant with the latest export controls.
Last week, the Nvidia CEO met with U.S. President Donald Trump, and was warned by U.S. lawmakers not to meet with companies connected to China’s military or intelligence bodies, or entities named on America’s restricted export list.
According to Daniel Newman, CEO of tech advisory firm The Futurum Group, Huang’s CNN interview exemplifies how Huang has been threading a needle between Washington and Beijing as it tries to maintain maximum market access.
“He needs to walk a proverbial tightrope to make sure that he doesn’t rattle the Trump administration,” Newman said, adding that he also wants to be in a position for China to invest in Nvidia technology if and when the policy provides a better climate to do so.
But that’s not to say that his downplaying of Washington’s concerns is valid, according to Newman. “I think it’s hard to completely accept the idea that China couldn’t use Nvidia’s most advanced technologies for military use.”
He added that he would expect Nvidia’s technology to be at the core of any country’s AI training, including for use in the development of advanced weaponry.
A U.S. official told Reuters last month that China’s large language model startup DeepSeek — which says it used Nvidia chips to train its models — was supporting China’s military and intelligence operations.
On Sunday, Huang acknowledged there were concerns about DeepSeek’s open-source R1 reasoning model being trained in China but said that there was no evidence that it presents dangers for that reason alone.
Huang complimented the R1 reasoning model, calling it “revolutionary,” and said its open-source nature has empowered startup companies, new industries, and countries to be able to engage in AI.
“The fact of the matter is, [China and the U.S.] are competitors, but we are highly interdependent, and to the extent that we can compete and both aspire to win, it is fine to respect our competitors,” he concluded.
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