On a mission to deliver clean fusion energy fast enough to meet humanity’s biggest challenges with SPARC® and ARC™.
Devens, Massachusetts, USA
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Big update: Half of our vacuum vessel, the very heart of our SPARC fusion machine, has landed in Devens, Massachusetts.
The vacuum vessel is the donut-shaped chamber inside SPARC that'll house our fusion fuel — a superhot cloud of charged particles called a plasma. The delivery of this key component means that our energy plans are literally starting to take shape. And it shows a big change inside tokamak hall as the once-quiet room begins to bustle with activity.
#PowerMoves #FusionEnergy
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Historic news for CFS: We’ve signed a landmark agreement with @Google, a multifaceted partnership that dramatically advances our commercial fusion energy mission:
⚡️Google signed an offtake agreement for 200 megawatts of power from our first ARC power plant
⚡️Google is increasing its corporate investment in CFS
⚡️Google has the option to procure power from future ARCs
This deal is a very strong signal that the world wants the clean, secure power that fusion offers. Together, we’re catalyzing the fusion market.
#FusionEnergy #PowerMoves
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Fusion is coming... to Chesterfield County, Virginia.
In an enormous development for CFS and for the commercialization of fusion energy, we've committed to build the world's first grid-scale fusion power plant, ARC, in Virginia.
We'll independently finance, build, own, and operate this first-of-its-kind technology so we can start generating clean, carbon-free energy in the early 2030's. We'll also collaborate with @DominionEnergy Virginia to help smooth ARC's path to the grid, benefitting from their development and technical expertise while helping the utility learn about fusion.
Check out what this means for CFS here: bit.ly/4gF0s1c
#PowerMoves
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CFS has raised >$1.8 billion in Series B funding to commercialize clean, limitless fusion energy. This is a diverse group of investors that believe in CFS & see commercial fusion energy as a game changing tech in the clean energy transition. #fusionenergy
ow.ly/LzTp50H0I9b
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Check out the latest construction photos from our commercial fusion campus in Devens, Massachusetts. We’re on track to demonstrate commercially relevant net energy with SPARC in 2025. And by the end of the year, our new manufacturing facility will be completed.
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Today, Commonwealth Fusion Systems announced we’ve raised $863 million in a new funding round — the second largest investment of committed capital into a deep tech or clean tech company ever. And the largest was our $1.8 billion Series B round in 2021.
This Series B2 funding, from investors spanning the globe, speeds up our push to get fusion energy’s clean, secure, affordable power onto the grid as soon as possible. Here’s how we’ll use the funding.
First, it lets us complete SPARC, the one-of-a-kind fusion machine we’re building right now at our headquarters in Devens, Massachusetts to demonstrate net fusion energy. Second, this investment lets us accelerate work on our next machine, the ARC fusion power plant we plan to build in Chesterfield County, Virginia — the first of many.
With this funding round, we broadened our range of investors. Those supporting our fusion energy mission include not just earlier-stage investors like venture capitalists and ultrahigh-net-worth individuals, but also sovereign wealth funds, pension funds, private equity firms, global industrial companies, utilities, and banks.
New investors in CFS include Brevan Howard, Counterpoint Global of @MorganStanley; Stanley Druckenmiller; FFA Private Bank in Dubai; Galaxy Digital’s Galaxy Interactive; @gigascale; @HOFCapital; @NevaSGR; @nvidia's NVentures venture capital arm; Planet First Partners; Woori Venture Partners US, and a consortium of 12 Japanese companies led by Mitsui & Co. and Mitsubishi Corp.
They join earlier investors that also returned, like @Breakthrough; @EmCollective; @eni; @Ventures_Future; Gates Frontier; @Google; @Hostplus Superannuation Fund; @khoslaventures; @lowercarbon; @safarpartners; former Google CEO @ericschmidt; @StarlightVC_, and Tiger Global.
What unites that diverse group: they see an enormous new industry forming as we harness the power source of the sun here on Earth. And CFS is leading that fusion energy charge.
#PowerMoves #FusionEnergy
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It’s time to bring the new computing power of AI to fusion energy.
Today, Commonwealth Fusion Systems and @GoogleDeepMind — giants in these two fields — revealed that we’ve joined forces to explore how AI can improve our SPARC fusion machine. Our researchers have begun applying artificial intelligence to different aspects of SPARC operations, a collaboration that ultimately holds the potential to accelerate our work to bring our clean, effectively limitless fusion energy to the electricity grid at scale.
AI methods could improve several areas of the computationally complicated realm of fusion control. For example, Google DeepMind’s technology could help us plan operations ahead of time, testing numerous configuration options to tune SPARC’s setup for the best results. Or AI could be used as a co-pilot for SPARC: train an AI model how to operate the tokamak’s control knobs based on various scenarios, give it a high-level goal like maximizing fusion power within the limits of the machine, then let it guide SPARC’s control system.
And Google DeepMind’s open-source TORAX software, which dovetails with this AI research, already has strengthened our simulation capabilities. We’re contributing to that project as well.
Google DeepMind has a top track record for applying AI to some of the most challenging problems. Its models defeated top human players in games like Go and StarCraft, helped design Google AI processors, and made Google data centers more efficient. Its Nobel Prize-winning AlphaFold AI leapfrogged earlier approaches to solving the famously hard protein folding problem that’s key to genetic and medical research.
The time is ripe for this collaboration, and we’re happy it’s underway. AI and fusion energy are 21st century technologies that’ll power the global economy for generations to come.
#FusionEnergy #PowerMoves #AI
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CFS and @MIT #PSFC have successfully tested the world’s strongest high temperature superconducting magnet -- the key technology on our path to commercial fusion! Read our exciting announcement ow.ly/GZAU50G5WAN
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It’s happening.
ARC, the world’s first grid-scale fusion power plant, is coming to Chesterfield County, Virginia. When we start generating power in the early 2030s, it'll be a colossal moment that'll open the grid to new clean, zero-carbon power that's available on demand.
Read more about this milestone from our CEO @BobMumgaard here: bit.ly/4gF0s1c #PowerMoves #FusionEnergy
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The @BONDbuild construction crew has been busy assembling bridge cranes in the Tokamak Hall. Soon, we'll start assembling SPARC!
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We’re revolutionizing #FusionEnergy. Our High-Temperature Superconductor (HTS) magnets are:
✅ Tested and peer-reviewed
✅ Breaking world records with a 20 tesla field strength
✅ Reducing the cost per watt of a fusion power plant by a factor of almost 40
✅ Meeting the requirements for commercial fusion
Learn more: bit.ly/3Ujy6jP
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Today's a big day for CFS, as we've officially moved in to our new company headquarters! Devens, Massachusetts will become the birthplace of commercially relevant, net-positive fusion energy.
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Today, while many contemplate pie, we still can't stop thinking about donuts. Here's one half of SPARC's vacuum vessel, the donut-shaped chamber where the fusion reaction will occur, making its way through the fabrication process.
Once completed, we'll ship the two halves to our campus in Devens, Massachusetts, and for SPARC assembly. Here, we'll mount 18 toroidal field (TF) magnets onto two stands, nine to a side, then thread each half of the vacuum vessel through its own set. It'll be like putting rings around a finger. The two halves will then be joined, part of a carefully choreographed process to put the whole tokamak together.
#PiDay #PieDay #SPARC #VacuumVessel
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Here’s our VP of Operations Darby Dunn standing in front of a life-size rendering of SPARC inside the CFS magnet factory.
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Exciting news today! New peer-reviewed papers released in a special edition of @CUP_Plasma predict SPARC, a compact fusion device designed and built by CFS and @MIT, will achieve net energy from fusion. #fusionenergy #fusion
cfs.energy/news-and-media/ne…
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Virginia is for fusion lovers.
Our CEO @BobMumgaard and @GovernorVA joined @SquawkBox this morning to discuss the historic announcement that ARC, the world's first fusion energy power plant, will be in Chesterfield County, Virginia. Fusion is the last energy source humanity will need — supplying clean, zero-carbon power on demand, using limitless fuel, offering inherently safe operations, and emitting no greenhouse gases.
Watch to learn how ARC will revolutionize how we power our world. cnb.cx/3VMJLJg #PowerMoves #FusionEnergy
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To get the first half of our vacuum vessel from Italy to the United States, we flew it on an Antonov An-124 Ruslan aircraft, an unusual four-engine cargo plane with room for the 48-ton component. Unlike passenger planes, the nose of the An-124 hinges upward to load and unload cargo.
The vacuum vessel is the heart of SPARC where our fusion fuel, heated to about 100 million degrees Celsius, will be contained. Now that half of it is at our headquarters in Devens, Massachusetts, our team is already getting to work preparing it for the next phase of the build.
#FusionEnergy #SPARC #Aviation #PlaneSpotting
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Less than three months after announcing our partnership to sell Google power from our first ARC fusion power plant, we now have a second customer: @eni, an integrated energy company based in Italy with operations in 60 countries. Through this power purchase agreement, Eni will buy more than $1 billion of clean, secure, safe fusion energy from our first plant in Chesterfield County, Virginia.
The deal shows the value of fusion energy and CFS’ capabilities to deliver it to a diverse set of customers.
Google is a hyperscaler, and the 200 megawatts of power they’ve agreed to buy is useful for running their network of data centers packed with computing and AI hardware. Eni, on the other hand, brings a more industrial perspective, knowing firsthand the value of energy and the complexities of building and operating complex facilities at scale.
Fusion, the process that powers the sun, isn’t easy to reproduce on Earth, but CFS is making steady progress toward its goal of delivering power to the grid in the early 2030s. That progress is the foundation of confidence in our company. Both Google and Eni are early CFS investors too, but with these power purchase deals have broadened their CFS relationships.
#FusionEnergy #PowerMoves
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SPARC is more than 60% complete. So far, most of that progress has taken place outside of the central hall that’s the future home of our star-of-the-show SPARC tokamak.
The SPARC facility consists of five interconnected buildings that house different SPARC subsystems. Case in point: the utility building here — roughly twice the size of the tokamak’s hall — houses equipment to pull the heat that fusion generates out of SPARC during operation.
#FusionEnergy
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No, we didn’t lure a UFO into CFS headquarters. This photo actually shows our first D-shaped toroidal field (TF) magnet in the making, nestled inside a cryostat that cools it down for testing.
And of course some of the hundreds of people it took to design, engineer, and build it all. Stay tuned for test results as we build our first fusion energy machine, SPARC.
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The centerpiece of the SPARC motor-generator system has arrived! The generator will be used to convert stored mechanical energy in the world's largest 3600 RPM flywheel system into electromagnetic energy to drive fusion experiments at SPARC.
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For our extraordinarily powerful magnets, we’ve moved from R&D and engineering to manufacturing in our magnet factory. Our high-temperature superconducting (HTS) tech means stronger magnetic fields and thus a smaller fusion power plant. Take a look here to see our magnet factory crews making the magnets for our first fusion machine, SPARC.
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Our cryostat is here! Both halves of the device that will be used to cool our high-temperature superconducting magnets for SPARC arrived at the CFS magnet factory this week. Next step: installation.
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New rendering of SPARC released today in #JPP special edition. SPARC is a compact tokamak that will produce net energy from fusion for the first time in history. Credit: CFS/MIT-PSFC — CAD Rendering by T. Henderson
ALT Rendering of SPARC, a compact, high-field, DT burning tokamak, currently under design by a team from the Massachusetts Institute of Technology and Commonwealth Fusion Systems. Its mission is to create and confine a plasma that produces net fusion energy.
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We’re making fusion energy a reality.
In the last six months, we’ve taken over Tokamak Hall, where our SPARC device will live, and begun installing equipment. We're over 900 employees now, too. Keep an eye out for big SPARC components coming soon.
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Fusion isn’t 30 years in the future. We’re bringing it to life right now with experts in everything from welding to commercialization pulling together to put our clean, zero-carbon power onto the grid.
The progress is palpable. Step onto our production floor and you'll see daily changes.
The world’s need for #fusionenergy is urgent, and our job only starts with SPARC. After that comes our first power plant, ARC, and after that, thousands more ARCs. It's a big job, but our team is united by that common purpose, moving smart, moving fast, and moving together to build the future.
#PowerMoves
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We've been continuing assembly work on the large test cryostat that will test our HTS magnets before they're installed in SPARC. This week, we flipped the 23 US ton lid.
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Check out the latest progress inside our SPARC fusion facility with CFS Head of Tokamak Operations Alex Creely 👷♂️
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Major milestones have been achieved at CFS in the last 6 months.
Since June, we’ve:
👊 Established fully working production lines
🧲️ Doubled our TF Magnet pancake production rate
✅ Developed a fully operational cable magnet line
⏫ Accelerated installation of RF Systems
Now, it’s time to move from R&D → production. Watch to get a closer look into our progress.
#FusionEnergy #SutainableInnovation #CleanEnergy
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Major moment: our CSMC pulsed-power superconducting magnet aced its validation tests.
This key foundation for our SPARC fusion machine performed well while protecting itself from overheating problems. That clears the way for a new manufacturing phase. Learn more: bit.ly/4fJiZJG
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Both @swurzel and @ScottCHsu have done a great job tracking decades of progress toward net fusion energy — more power out than in. That goal, denoted Q>1, is a key step toward fusion energy commercialization. The researchers’ 2022 paper summarizes decades of results from dozens of machines.
Now Wurzel and Hsu are updating their research with newer results like the National Ignition Facility’s successful demonstrations. Projected results from our own SPARC machine, which we detailed in our own physics basis research papers, appear on their plots. We plan to push first for Q>1, but the machine is designed to reach Q=11.
For anyone who wants to track fusion energy progress, this unbiased assessment rises above much of the noise. Kudos to these researchers for helping it keep pace with our fast-moving industry.
Read more: fusionenergybase.com/article…
#FusionEnergy
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Getting half of SPARC'S vacuum vessel to Devens, Massachusetts, was no easy task.
Its smooth journey from Italy to our headquarters over the course of a few days required a lot of moving parts — multiple teams, different cranes, one big plane, and two big trucks. This inside look shows the painstaking planning and execution behind the whole operation.
#FusionEnergy
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Fusion gets closer with successful test of new kind of magnet at MIT start-up backed by Bill Gates cnb.cx/3yTjc7a @CatClifford
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Yesterday in Chesterfield County, our ARC fusion power plant moved one step closer to the grid as the Chesterfield County Board of Supervisors unanimously approved a conditional use permit for the project. The permit, which finalizes the Chesterfield County Planning Commission’s unanimous approval in August, means our planned site is now zoned for fusion energy generation.
This is a historic moment: This site at the James River Industrial Center is the first property in the US that’s zoned specifically for a fusion power plant. And it’s an important step in our journey to bring ARC’s clean power to the grid in the early 2030s.
Next we’ll start working on approvals to start construction, connect ARC to the grid, then turn it on so it can generate its 400 megawatts of power.
Just as we did with our SPARC fusion demonstration machine — under construction now in Devens, Massachusetts — we'll continue to meet consistently with community members, businesses, and state and local government officials. We know fusion is new to most people, and we consider this outreach some of our highest priority work.
This is just the beginning. We look forward to continuing this conversation on fusion energy.
#FusionEnergy #Virginia
ALT A gray building with a larger central hall, orange highlights, and a Commonwealth Fusion Systems logo on the front.
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We're celebrating a major building milestone this week: thanks to @BONDbuild, the Tokamak Hall is officially weather-tight and ready for SPARC assembly!
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Heating a plasma to 100M Celsius is no easy act. Behold the radio frequency (RF) delivery system for our SPARC fusion machine.
The RF system delivers radio waves to heat the plasma — a process related to how a microwave heats food. But in this case, the power of our RF system is equivalent to about 40,000 household microwaves.
#FusionEnergy
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Tomorrow, @SecGranholm @SenMarkey @SenWarren @RepLoriTrahan @MassLtGov will join us in Devens, Massachusetts for the official opening of our new commercial fusion campus.
Tune in live from 10:45AM ET ⚡ nitter.app/i/broadcasts/1yoKMZqQN…
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Meticulous #manufacturing is key to making SPARC, the tokamak we’re building to produce fusion energy.
Check how our partner @WalterTostoSpa crafted the inner shell of the vacuum vessel at SPARC’s heart. It’ll house a superheated plasma that generates #fusion power.
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It's been a busy six months since we moved into our commercial fusion energy campus in Devens, Massachusetts.
Here's a look at what the CFS team has been building lately, and what comes next:
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What’s CFS been up to in the last six months?
Picking a location for our first fusion power plant, ARC, and making magnets for our net fusion energy demonstration machine, SPARC.
Check the twice-yearly update video from CEO @Bobmumgaard for the details — and a sneak peek at some new fusion hardware on the way.
#FusionEnergy
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CFS CEO Bob Mumgaard shows @SecGranholm, @SenMarkey, @SenWarren, @RepLoriTrahan, and @MassLtGov around the SPARC facility, the world’s first commercially viable net energy fusion machine now under construction.
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"Fusion’s potential impact on global energy systems is profound. It offers energy independence by decoupling power generation from natural resources, making it ideal for urban centers and regions with limited land."
– @somband1970 reports on fusion energy after a conversation with CFS CEO and Co-founder @BobMumgaard. 1/2
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This summer CFS and @MIT will demonstrate our key magnet technology. This 20 Tesla magnet will be the largest magnet of its kind and enable our approach to commercial #fusionenergy.
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The incredible work of our world-class team and collaborators has allowed us to set and meet our ambitious milestones as we work to commercialize fusion energy. We are proud that this amazing group of investors has confidence in our ability to deliver. #fusionenergy
Cambridge energy startup smashes Massachusetts record for venture capital bos.gl/bAjDCUo
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This month, CFS received a broad-scope radioactive materials license from the Commonwealth of Massachusetts for our SPARC fusion machine. By showing we’ve equipped ourselves with the people and procedures to safely handle and store these materials, we’ve taken a big step ahead on the path toward operating SPARC.
The license also shows our ability to tackle the broad range of real-world requirements to get SPARC working. Although our effort started with fusion’s science and engineering challenges, it’s extended much farther to jobs like scaling manufacturing, building supply chains, and selecting sites. All that expertise will extend from today’s SPARC project to our work on its power plant successor, ARC.
bit.ly/4eWFz15
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Behold the inner shell of our tokamak vacuum vessel, built as a single component then split in half for speedy, precise manufacturing. It’ll hold hot plasma to produce fusion power. #BTS footage of @WalterTostoSpa halving the vessel. #ToughTech #FusionEnergy #Manufacturing
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We’re in a race against time to develop scalable, sustainable fusion energy for our planet. Standardized measurements and peer-reviewed data are critical to driving progress. Read CEO's @BobMumgaard's open letter on industry accountability and innovation efforts here: tinyurl.com/bdhmvjtz
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On Monday, CFS announced a power purchase agreement with @eni, one of the largest energy companies in the world, in a deal worth more than $1 billion.
But how can we sign an agreement like that — or the Google deal that came just three months before it — without yet having demonstrated a machine that actually produces fusion energy?
In short, by showing the steady, step-by-step progress we promised years ago as the fastest, surest path to this new form of energy. For a look at what made the Eni and Google deals possible and what makes them so important check the blog post from our Chief Commercial Officer Rick Needham.
Our journey started with the type of fusion device we’ve chosen to build, the tokamak, which is the best scientifically understood approach to the fusion process of combining light elements into heavier ones. Our path then proceeds through many detailed tests, including large-scale magnet prototypes and extensive computer modeling.
And the progress continues through SPARC, the fusion machine we’re building now to demonstrate net fusion energy. That’ll prove most of the technology in our later ARC fusion power plant — and set the stage for the arrival of the last energy source humanity will need.
Read the post here: blog.cfs.energy/fusion-forwa…
#FusionEnergy
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Time for a new 6-month update from CEO @BobMumgaard about what we’re up to at Commonwealth Fusion Systems:
️️
⚡️ See the site in Chesterfield County, Virginia, for our first ARC fusion power plant
️⚡️ Hear how Google has agreed to purchase 200 megawatts of power — half of ARC's output — starting in the early 2030s
️⚡️ See new SPARC tokamak parts due soon, including its vacuum vessel and first magnets
️⚡️ Learn about the supply chain we’re building that helps SPARC and also the broader fusion industry
Bob Mumgaard: “When we founded the company, we had a roadmap: Start with magnets, then build a factory to make more magnets for SPARC, build and operate SPARC, go build ARC, build more ARCs. We’re still on that same roadmap, and it’s all coming together."
#FusionEnergy #Science
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The CFS mission is to make fusion energy a reality.
Learn more and join our team: cfs.energy
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“The central dynamic of the fusion race is clear: the United States laid the scientific groundwork; China is positioning to win the industry… The nation that leads in fusion will secure significant economic advantages, ensure its energy independence, and maintain its technological edge in critical areas, including AI and national security.”
So concludes the @scsp_ai’s Commission on Scaling Fusion Energy in a report released today (see link below) that urges the United States to make rapid fusion energy commercialization a top priority:
1️⃣ The president should declare fusion energy to be a national security priority through an executive order.
2️⃣ The Department of Energy should support fusion energy research, development, and demonstration with a $10 billion investment. That would fund new infrastructure to close technical gaps, public-private partnerships that de-risk private sector fusion designs, and a new tier in DOE’s Milestone-Based Fusion Development Program to demonstrate power plants.
3️⃣ The federal government should take strategic actions to support efficient regulations, lead in using digital design tools like AI, and develop a fusion supply chain and workforce.
Why this big push? Among the report’s findings:
▶️ “China, recognizing fusion’s strategic importance, is mobilizing massive state resources not only to pursue scientific breakthroughs but also to build the infrastructure, supply chains, and industrial capacity required for deployment at scale — a proven strategy Beijing has already used to lead sectors like solar panels and advanced batteries.”
▶️ "Since 2023, China has mobilized over $6.5 billion across its fusion enterprise, almost three times the funding appropriated to the Department of Energy’s Fusion Energy Sciences (FES) Program in roughly the same period of time."
▶️ “China is producing ten times more fusion PhD graduates than the United States, a direct function of government funding.”
▶️ “The United States’ scientific community identified the important infrastructure in 2020… but DOE has not executed this plan. China, on the other hand, is backing its fusion goals with massive infrastructure projects.”
Read the report here: scsp.ai/wp-content/uploads/2…
#FusionEnergy #China
ALT A Venn diagram showing China's growing advantages in key areas for fusion energy, including government funding, talent, R&D infrastructure, and research publications. The United States leads in scientific breakthroughs and private funding but isn't gaining in any area.
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"@Google and Massachusetts-based Commonwealth Fusion Systems announced a deal Monday in which the tech company bought 200 megawatts of power from Commonwealth’s first commercial fusion plant, the same amount of energy that could power roughly 200,000 average American homes."
Read more from @CNN: cnn.com/2025/06/30/climate/f…
#FusionEnergy #AI
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At our new magnet factory in Devens, Massachusetts, CFS will manufacture high temperature superconducting magnets for our net energy fusion device, SPARC—and then our first fusion power plant, ARC. Here’s a look inside with construction almost completed.
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Why work on our ARC fusion power plant when we haven't yet switched on our SPARC demonstration machine? It's a fair question. And here's our answer: at CFS, we've deliberately charted a path to fusion energy that lets us work in parallel on multiple projects.
Our new $863 million in Series B2 funding enables us not just to finish SPARC but also to concentrate more attention on ARC. The point of the exercise: spread fusion energy as widely as possible as fast as possible, because we believe humanity will benefit.
Now we're laying out a lot of the detail behind this approach. 🧵1/2
#FusionEnergy #PowerMoves
ALT A large industrial room packed with high-tech cooling equipment, green valves, silver tanks, with an orange crane overhead.
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It’s time for a fresh look inside the facility where we’re building SPARC, a machine called a tokamak we’re building to demonstrate fusion energy’s commercial viability. In this tour, Alex Creely, Director of Tokamak Operations and tour guide shows how the first element of the tokamak is installed — and how we’ve begun putting some of the supporting hardware through its paces.
Check the tour video to see:
• Our new cryostat base, SPARC’s foundation, positioned with millimeter accuracy
• The radio frequency heating building, home to electronics that will heat SPARC’s fusion fuel
• The utility building, where we have the cryogenics to keep SPARS’s magnets cold.
• The operations building for diagnostics we’ll use to operate SPARC and learn from it
Ultimately, we’ll apply what we learned to our ARC power plant — both how to design it and how to run it. Our mission is to deliver many ARC power plants, but SPARC is the machine that gets us there.
#FusionEnergy #Energy #Science
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To make our SPARC fusion machine, we have to look at the big picture but also sweat the details. These close-ups show the precise machining we employ to make the steel cases for our 18 D-shaped toroidal field magnets. Stay tuned to see what our magnet cases look like in full. #FusionEnergy #Macro
ALT A high-contrast geometric pattern of curves formed by machining a steel case
ALT A high-contrast geometric pattern of curves and straight lines formed by machining a steel case
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"Everything is about to change in Tokamak Hall."
This month, we brought a key component of our prototype fusion machine, SPARC, into its final home inside the SPARC facility in Devens, MA. It's the cryostat base — the foundation of SPARC and a major milestone in its buildout.
Along with its job to support SPARC’s mass, the 75-ton base acts as a conduit for fundamental systems like cryogenics and fuel lines that connect to the machine. It's also a vital boundary protecting the magnets inside SPARC from the outside environment so they function at full strength.
SPARC’s cryostat is designed to be so well sealed that only a cubic centimeter of gas could leak over 30 years.
Learn more and watch the full video on our blog: blog.cfs.energy/cfs-takes-it…
#PowerMoves #SPARC #FusionEnergy
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High-temperature superconducting tape is enabling stronger fusion magnets that will unlock the path to commercial fusion energy.
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An exciting week for the future of fusion, as we topped off the roof of our new SPARC facility at our commercial fusion campus in Devens, Massachusetts. Many thanks to @BONDbuild for keeping us on track for net fusion energy in 2025!
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Come see the mega-magnet that could radically improve how we get the electricity that modern life demands. We're seriously honored to be able to show this special pop-up exhibit at the Computer History Museum in the San Francisco Bay Area that runs from Feb. 14 to March 23.
Just like the transistor led to the computing revolution, high-temperature superconducting (HTS) tape enables new components that make fusion energy practical. One of those components is the “pancake” we’re displaying, a high-tech slab of metal packed with a spiral of superconductors. It’s part of the record-setting superconducting magnet called TFMC that proved its worth in a crucial 2021 test, enabling CFS to grow to today’s work building a full-scale fusion machine.
We’re showing the magnet at #FusionXInvest this week. It’s all part of a display showing how fusion energy works and how businesses will use it to power the grid.
#FusionEnergy #PowerMoves
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The goal for our fusion machine, SPARC, is to produce net energy — more power out than in. The power out is the part that makes the pursuit of fusion energy worth it. But the power in is also an essential part of the process.
Alongside the radio frequency system that heats the plasma, SPARC also requires power that goes straight to its magnets. For that we build hefty electrical conduits called current leads (seen here). You can think of these like giant versions of the power adapters you use for your phone when traveling abroad.
Like the magnets themselves, these components use high-temperature superconducting (HTS) tape to shoulder the electrical load. We'll cool them with liquid nitrogen to 80 kelvin (-316°F or -193°C) to enable their current-carrying abilities.
#FusionEnergy #Magnets #Macro
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Let’s say you want better fusion power plants. How about designing some better metals — using a computer?
CFS won a $2.5 million award to employ advanced computing technologies to design better materials for our ARC fusion power plant.
The funds, from DOE’s ARPA-E program, will fund CFS to design the materials by combining multiple integrated computing models, then in combination with three partners, manufacture candidates and test them under conditions similar to our fusion power plant.
The reason for the work: Developing new materials superior to today’s options will make power plants like ARC easier to maintain and more economical as a result. We’re laser focused on commercializing fusion energy to meet rising energy demands and tackle climate change, and every improvement amplifies fusion’s success.
We’re bringing three areas of accelerating progress together — computers, fusion, and fabrication — to deliver this new power source. bit.ly/40xSP8m
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With #AI breaking barriers, energy demands are poised to skyrocket. #FusionEnergy presents the solution: sustainable, abundant, dependable power 24/7.
Learn more in this thread. ⬇️
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Through 62 presentations this week, researchers from Commonwealth Fusion Systems (CFS) and our collaborators are shining a physics spotlight on our SPARC fusion demonstration machine — and how it paves the way for our ARC power plant.
Those presentations are at the premier conference for tackling the deepest challenges of fusion technology, the @APSphysics's Division of Plasma Physics annual meeting — APS-DPP for short. Plasmas, the superhot clouds of charged particles that are fusion’s fuel, are hard to control. But doing so in machines like SPARC and ARC opens the door for a clean, affordable new source of energy.
CFS presentations will address subjects like handling plasma disruptions, understanding plasma stability, and managing the plasma’s hot exhaust. Sharing such research with colleagues at APS-DPP is one of the best ways that researchers at fusion energy companies can uncover and solve such plasma problems.
“You can delude yourself — being off in a corner thinking you’ve solved every issue — but there could be dozens of other problems you aren’t aware of,” said Phil Snyder, Vice President of Plasma Physics at CFS.
CFS is building SPARC now at our Massachusetts headquarters. That’s also where we make magnets such as this D-shaped toroidal field (TF) magnet in a testing chamber, shown here surrounded by the team that helped to manufacture it.
The next major milestone for CFS is using SPARC to demonstrate net fusion energy — more energy out than in, a scientific goal called Q>1. Then SPARC will be used to fine-tune ARC, work CFS is discussing at APS-DPP.
“What we’re going to accomplish on SPARC is testing our models and our understanding in a physics environment indicative of ARC,” Snyder said.
For more details, check our blog post: blog.cfs.energy/how-new-spar…
#FusionEnergy #Science #SPARC
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"Commonwealth Fusion Systems’s $863 million Series B2 funding round brings the company’s total capital raised to nearly $3 billion, cementing its position as the best financed, private-sector fusion venture by a wide margin, and with the most diverse cap table, highlighting the extraordinary investor confidence CFS has built relative to many of its competitors." –FusionX Group CEO Stuart Allen. fusionxinvest.com/insight/90…
#FusionEnergy
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"Fusion has no greenhouse gas emissions, is intrinsically safe and can provide continuous power, which we can combine with renewables to decarbonize the energy system.”
With SPARC on track for 2025, we're getting close to safe, reliable zero-carbon power.
ft.com/partnercontent/eni/th…
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This Earth Day, we celebrate all those around the world who are working tirelessly to combat climate change with clean energy solutions.
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It’s time to detail the third of the six milestones every company must reach on the way to commercial fusion energy. Our CEO @BobMumgaard laid these out last year in an open letter to help separate the progress from the puffery — a guide for outside observers to track how well fusion energy companies are truly doing (cfs.energy/news-and-media/bu…).
Milestone 3 means building a fusion machine that approaches conditions intense enough for fusion to take place, in a situation somewhat representative of what you’ll see in a fusion power plant. It’s a lot harder to reach than the first two milestones — especially the need to insulate the plasma at the heart of the machine. Not only must the plasma be hot, but it must stay hot on its own, like a well-insulated cup of coffee you don’t need to reheat all the time.
Success in milestone 3 means scoring high on a measurement called the triple product that reflects your plasma’s density, temperature, and insulation. Many fusion machines have faltered trying to get there.
For details, check Bob's blog post: blog.cfs.energy/fusion-energ…
#FusionEnergy
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CFS is rewriting the rules of the power grid, moving toward sustainable, accessible, clean energy. But how will our tokamaks turn fusion into electricity? Alex Creely, Director of Tokamak Operations, details our approach to capturing heat and scaling with existing infrastructure.
#FusionEnergy #CleanEnergy #Sustainability
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Fusion energy will be an adaptable new power source when it fires up in a few years to help meet growing power demand. It's a steady source that'll complement wind and solar and it'll enable transformative new industries. Discover why fusion is a good fit for the grid's needs: blog.cfs.energy/cfs-low-cost…
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100 days into a new administration, it's good to see @ENERGY prioritize commercial fusion energy. Efforts that help the private sector tackle the practical challenges of fusion energy, not just its scientific foundations, means the US can tap into fusion's economic and security benefits and make the electricity grid more robust as soon as possible. Learn about some of the DOE's recent fusion energy work here: energy.gov/science/articles/…
#FusionEnergy #EnergySecurity
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Those governments that actively support the commercial fusion industry will chart a prosperous path into the future.
Fusion's advantages — clean, steady power generation, abundant fuel, and flexible siting — make it the last new energy source the planet needs. Fusion at scale can deliver economic benefits from helping to meet growing power needs, employing tens of thousands of people, and supporting a robust supply chain. For the US, fusion could give the country more control of its destiny. But compared to other countries like China, US fusion commercialization investment is lagging.
Read more on the Tokamak Times:
blog.cfs.energy/the-race-to-…
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New glass has been installed at the SPARC facility that will showcase what’s happening inside our entryway and diagnostics lab.
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“We’re about halfway through building the first prototype outside of Boston. In about 2 years we’ll turn this machine on. That’ll be an important point in the world where we’ll have, for the first time, industrial-scale fusion power being created by people.” – our CEO @BobMumgaard, speaking to @ndtv Group Executive Editor @VishnuNDTV at #WEF2025 #FusionEnergy #EnergyTransition 1/2
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Today's @BostonGlobe @davabel article highlights fusion progress. As our CEO, Bob Mumgaard says, fusion is "a solution that can scale to the size of the problem that decarbonization requires." #fusionenergy
bostonglobe.com/2021/12/22/s…
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A look into the site where SPARC will soon sit, as the construction crew makes progress every day inside our Tokamak Hall.
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"You're transitioning from building the facility...to actually starting to build the tokamak itself. That is an awesome milestone." –CFS' Alex Creely on the arrival of the cryostat base to make SPARC. Featured in @arstechnica's look at the state of commercial #FusionEnergy by @j_timmer.
arstechnica.com/science/2025…
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CFS was honored today to host Secretary @JohnKerry and @ENI CEO Claudio Descalzi at our commercial fusion campus. They've long believed in fusion energy as a climate solution, and we're grateful for their efforts to help accelerate the path to commercialization.
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To keep our magnet factory humming, we sometimes rearrange work stations for speed and flexibility — like adding a second cryostat test stand to make sure our magnets are up to scratch.
Here, after a magnet test, two technicians oversee the removal of a lid from one of the cryostat test stands that are now in use to check magnet performance at low temperature and in a vacuum. With two test stands, we can test multiple magnets in parallel, and that'll help us get these magnets ready for SPARC that much faster.
#FusionEnergy #Magnets
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There's nothing like a fresh coat of paint!
With painting in the SPARC facility almost complete, next week the construction crew will start mechanical, electrical, and plumbing work inside the Tokamak Hall.
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We were honored to host @MassGovernor today at our commercial fusion energy campus in Devens, Massachusetts, where we talked about the state’s leadership on clean energy and the role CFS is playing to advance that leadership.
During her trip, the governor and our CEO @BobMumgaard toured the CFS corporate headquarters, our SPARC fusion facility, and the manufacturing plant where we’re building our groundbreaking magnet technology.
The SPARC project will demonstrate here in Massachusetts for the first time in history that fusion energy can work in a commercially scalable machine. That paves the way for our ARC power plants that'll bring clean, secure, and affordable energy to the grid.
Core to the SPARC project and ARC power plants is our high-temperature superconducting (HTS) magnet technology. This clean-tech innovation was born in Massachusetts, thanks to a research collaboration with @MIT’s Plasma Science and Fusion Center. CFS is now building these magnets at scale in our factory in Devens. After making SPARC’s magnets, we plan to build HTS magnets for the ARC power plant in Devens, too.
We look forward to working with Gov. Healey and her administration as we look to expand our presence in the Commonwealth of Massachusetts. Thanks to the governor and @MassEEA and @MassEOED for coming by.
#FusionEnergy #Massachusetts
ALT Mass. Gov. Maura Healey, left, and Commonwealth Fusion Systems CEO Bob Mumgaard talk in front of two large stacks of the company's magnet "pancakes" in the CFS factory. Each pancake is a flat, D-shaped stainless construction housing a coil of copper-colored superconducting material.
ALT Mass. Gov. Maura Healey and Commonwealth Fusion Systems CEO Bob Mumgaard stand in front of a copper-colored wall with the CFS logo and name.
ALT Commonwealth Fusion Systems CEO Bob Mumgaard, left, stands beside Mass. Gov. Maura Healey in front of a glass-fronted two-story building. They're wearing orange safety vests and blue hard hats and are talking to a yellow-shirted worker standing by a pile of dirt on a construction site. A group of others wearing safety equipment follow the pair.
ALT Commonwealth Fusion Systems CEO Bob Mumgaard, arms gesturing, details the company's fusion technology to Mass. Gov. Maura Healey. The two and a group of others are standing on a balcony overlooking orange metal assembly stands and the disc-shaped foundation of the company's SPARC fusion machine. Above them is a an orange overhead crane.
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Happy New Year from CFS! It’s been an extraordinary year of progress toward commercially-relevant, net-positive fusion energy, and we look forward to 2023 ringing in even more.
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At CFS, our team has achieved remarkable progress within a span of just six months! We have successfully developed fully functional magnet lines, actively producing our PF magnets.
Bringing us one major step closer to transforming the energy landscape with #FusionEnergy.
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C-mod paved the way for the revolutionary era we’re in today. It gave us a look into the potential of a fusion powered future.
SPARC was born from C-mod's legacy and the determination of those who built it. It’s the #FusionEnergy that will better the future for everyone.
February 12 is a day of reflection at @CFS_energy: the day we learned MIT’s Alcator C-Mod tokamak program had lost funding. But it was also the moment when we started thinking bigger - that we could commercialize fusion. And @cfs_energy was born. #energytransition #climateinnovation #fusionenergy
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We’re hard at work in our Devens, Massachusetts magnet factory, constructing and testing magnet assemblies for our SPARC fusion machine. We think it’ll be the first commercially focused machine to produce net energy, and it’s the foundation for later ARC fusion power plants that’ll produce net electricity.
#FusionEnergy #Manufacturing #Sustainability
ALT Two workers check a section of a TF (toroidal field) pancake on a large orange table at the Commonwealth Fusion Systems magnet factory in Devens, Massachusetts.
ALT Three workers wearing safety goggles gather around a small testing device on a table at the Commonwealth Fusion Systems magnet factory in Devens, Massachusetts.
ALT A group of employees gather for a discussion inside the Commonwealth Fusion Systems magnet factory in Devens, Massachusetts. In the foreground are two ring-shaped magnet components.
ALT An employee seated and working inside a large TF (toroidal field) pancake at the Commonwealth Fusion Systems magnet factory in Devens, Massachusetts.
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At @CFS_energy, superconductors are our jam. By carrying electrical current with no resistance whatsoever when you get these materials cold enough, superconductors let us build the staggeringly powerful magnets crucial to our fusion power effort. "Resistance is futile," we joke. 🧵 1/n
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“It’s easy to fall into a trap that because energy has been done a certain way, it will always be done that way.” – That’s @BobMumgaard today at @wef in Davos, Switzerland, saying our work to bring fusion energy to the grid means it’s also time to rethink how we power our homes, vehicles, and industries. 1/7 #WEF2025
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It’s a great moment to celebrate milestones at CFS — in more ways than one.
Today we announced we’re done manufacturing one of our key magnets and putting it through a rigorous, month-long battery of performance tests — which it passed. That achievement unlocked a payment from @ENERGY’s Milestone Based Fusion Development Program, an important fusion energy industry catalyst, after DOE’s panel of experts validated our results.
Marking the occasion on Monday, @SecretaryWright and @MassGovernor Maura Healey visited our headquarters to see how we test our magnets and discuss how we’re working to bring fusion energy to the electricity grid, at scale, as fast as possible.
Here’s the background for this bipartisan visit.
Our high-temperature superconducting magnets are a key breakthrough that’ll let us make fusion machines to be more compact than was previously possible. That includes both SPARC tokamak that we’re building at our headquarters in Devens, Massachusetts, and the ARC power plant we’re planning to put on the grid in Chesterfield County, Virginia.
DOE’s Milestone program provides important independent validation that our magnet technology is up to scratch — in this case a production version of a D-shaped toroidal field (TF) magnet that’s destined to confine and control SPARC’s superhot fusion fuel. We tested the magnet with high current and magnetic fields under conditions that mimic SPARC’s operational modes.
The Milestone program is an important tool to accelerate the commercial fusion energy industry’s progress. It validates participating companies’ general fusion approach and their specific technological milestones, providing useful assurance to investors and other stakeholders. And it does so with minimal risk to taxpayers, since the government pays pre-agreed awards for pre-agreed milestones only when the companies are successful.
#FusionEnergy #SPARC #PowerMoves
ALT Two CFS workers help build a toroidal field magnet, a stack of D-shaped metal plates resting on an orange stand.
ALT Commonwealth Fusion Systems CEO and Co-founder Bob Mumgaard, left, tours the company's magnet factory with Energy Secretary Chris Wright at the company's headquarters in Devens, Massachusetts. The men wear protective eyewear as they walk through a factory floor, orange metal structures on one side and green tanks of gas on the other. Wright visited CFS on Sept. 29, 2025.
ALT CFS CEO and Co-founder Bob Mumgaard discusses with Energy Secretary Chris Wright how CFS tests its D-shaped toroidal field magnet technology inside a cooling chamber called a cryostat. The D-shaped metal magnet structure in its center of a large, wide silvery cylindrical test chamber with workers inside the chamber making adjustments. Wright visited CFS on Sept. 29, 2025.
ALT From left to right, Massachusetts Governor Maura Healey, CFS CEO and Co-founder Bob Mumgaard, and Energy Secretary Chris Wright stand in front of Commonwealth Fusion Systems’ headquarters.
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It’s a new year at our brand new headquarters in Devens, Massachusetts, and we’re settling in on our quest to bring SPARC to life.
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Bloomberg: "Not so long ago, fusion energy was confined to fiction. Increasingly, it looks like a prosaic engineering problem: hard, expensive, time-consuming — but ultimately solvable. That’s a challenge Americans should embrace."
bloomberg.com/opinion/articl…
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Today @SecGranholm joined @MassLtGov, @SenWarren, @SenMarkey, @RepLoriTrahan, and a host of state and local leaders to officially open our commercial fusion campus, on the fastest path to bring clean fusion energy to the world: cfs.energy/news-and-media/cf…
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If there was one “score” you could give #FusionEnergy machines, it would be the Triple Product. This calculator indicates how close you are to achieving a practical energy source. Alex Creely, our Director of Tokamak Operations at CFS, explains how balancing temperature, density, and confinement time are key to unleashing clean, abundant energy. 🌟 #CleanEnergy #ClimateInnovation
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Watch as we celebrate the official opening of our new commercial fusion campus in Devens, Massachusetts with @SecGranholm @SenMarkey @SenWarren @RepLoriTrahan @MassLtGov 🎥
nitter.app/i/broadcasts/1yoKMZqQN…
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The U.S. Department of @ENERGY has a new tool in its toolbox for building the fusion energy future: the Private Facility Research Program (PFR). It’s an opportunity for university and laboratory researchers to win government funding when joining our SPARC effort. It’s a good signal that the US fusion program is pushing toward commercialization.
Interested? Researchers must begin applying to DOE by Feb. 19. Read about it at our blog: blog.cfs.energy/sparc-select…
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CFS has raised $84 million in a series A2 fundraising round to accelerate the development of commercial fusion energy. We are excited to have new investors Temasek, Equinor, and Devonshire Investors on board. #fusionenergy
cfs.energy/press/commonwealt…
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"We realized if we really wanted to make a difference in mitigating climate change, we had to go fast."
Co-founder and Chief Scientific Officer Brandon Sorbom shares the CFS origin story, from a class project at MIT to the world's largest private fusion company:
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CFS Chief Science Officer and Co-founder @BrandonSorbom offers a ground-level view of how we'll assemble the SPARC fusion machine inside Tokamak Hall. In the third video of this three-part series, Brandon shares a surprising detail on the cranes we use to handle SPARC's large components. Stay tuned for more episodes to come from around the CFS campus.
#FusionEnergy #Science
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A big piece of the #SPARC puzzle just landed on campus. Any guesses what we’ve got here? More on this soon.
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For our super-strong magnets, all paths to our SPARC fusion machine lead through this big cylindrical chamber. It’s called a cryostat, and we have two of them here at CFS so we can put all our magnets to the test before they become part of SPARC.
Between tests, our team dons clean suits to scrub the inside of the cryostat for the best testing environment.
The cryostat cools down our magnets so we can ramp up the electrical current to create a powerful magnetic field. To help keep the magnets cold, we pump all the air out of the cryostat. Recreating some of the SPARC environment lets us spot problems and make sure the magnet is up to scratch. #FusionEnergy
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With the announcement of our new award from @ENERGY, now is the right time to take a look at its Milestone Based Fusion Development Program — its successes so far, and how it needs to dramatically expand if it’s to really fulfill its potential to speed clean, safe, secure fusion energy to the power grid.
This week, we at Commonwealth Fusion Systems announced that a production version of our groundbreaking magnet technology passed our rigorous testing, clearing it for use in our SPARC fusion machine. The Department of Energy’s Milestone program validated our tests, confirming that the magnet is up to scratch and awarding CFS $8 million after we reached this milestone.
It’s an important display of how the Milestone program can be effective: By validating our technology, stakeholders get assurance that we’re doing what we need to push fusion energy toward the nation’s electricity grid.
With milestone-based approaches, the taxpayers don't bear any of the risks. If we don’t meet one of our milestones, the government doesn’t have to pay. If we were late or had to spend more than we expected, that’s our problem, and the government wouldn’t have to pay early or more than we agreed upon.
It’s a good model. Milestone-based approaches are effective policy, and we know they work. Just look at the commercial space industry, which pioneered this approach at NASA.
There, $788 million in federal investments — $1.2 billion in today’s dollars — helped build the US space industry to its present $143 billion annual market, sparking new industries like satellite-based broadband and emergency phone messaging.
But with DOE’s Milestone program, we’re only in the first phase, and the federal government has only appropriated a small fraction of the $415 million it authorized to implement for a three-phase effort. Beyond that, we’d like to see the Milestone program expanded to accelerate the construction of fusion power plants through a demonstration phase.
That could put the DOE’s Milestone program in the same league as NASA’s success.
To read more, check our blog post on how to improve the Milestone program: blog.cfs.energy/department-o…
#FusionEnergy #PowerMoves
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