Billionaires Put $2 Billion into Commonwealth Fusion Systems

Commonwealth Fusion Systems and MIT’s Plasma Science and Fusion Center (PSFC) have demonstrated a magnet with a record-breaking 20 Tesla magnetic field. This is the core technology that they planned to create. They now have to mass produce the supoerconducting magnets one tenth the cost cost and assemble them as part of a net energy gain fusion system by 2025. They have $1.8 billion in recent funding from Bill Gates, Jack Ma, Richard Branson and many other funds and investors. They previously had gotten over $200 million so they now have total funding over $2 billion. The 20-Tesla magnets will make the Commonwealth Fusion reactor 2.5% of the size (1/40th the size) than the ITER tokamak reactor which will use 11-tesla magnets.

The 20 Tesla magnets will be used in SPARC. The SPARC demo unit began construction in 2021 and they hope to demonstrate net energy gain for the first time in history by 2025.

Daniel Jassby, a retired physicist from the Princeton Plasma Physics Laboratory (PPPL), says PPPL’s Tokamak Fusion Test Reactor and the UK’s Joint European Torus, the only two fusion reactors in the world to have used tritium, took 10 years of experimenting with hydrogen and deuterium alone. If the warm-up period could be halved, SPARC’s tritium operation wouldn’t be likely to occur before 2032. The SPARC net gain demo reactor with construction completion targeted for 2025 will target 10 seconds bursts of power. Jassby is saying it will take years to get the system up to full operation and power levels. It would not be practical or reasonable to start work on the ten times larger commercial reactor before they learn if things are really working with the demo reactor.

SPARC would be the size of existing mid-sized fusion devices but with a much stronger magnetic field. SPARC plans to verify the technology and physics required to build a power plant based on the ARC fusion power plant concept. SPARC is designed to achieve this with margin in excess of breakeven and may be capable of achieving up to 140 MW of fusion power for 10 second bursts despite its relatively compact size. The resulting plasmas are expected to generate at least twice as much energy as is required to sustain themselves at high temperatures (200 million K), giving a fusion gain Q greater than 2, with an expected Q ≈ 11.

A 19 Tesla field is powerful enough to lift 403 Boeing 747s. Each of the SPARC demo systems would have 18 magnets and each magnet would have 166 miles of superconducting tape.

Commonwealth Fusion is trying to make a compact Tokomak with more powerful superconducting magnets. They wanted a commercial tokamak by 2033 but the current target is 2035 for a commercial tokamak. MIT spunout a tokamak fusion project into Commonwealth Fusion systems. They want to apply modular designs to high-temperature superconductors. They want to get to stronger magnets that will shrink the size and cost of the potential nuclear fusion reactor. Improved magnets would improve any nuclear fusion design that involves confinement of plasma. There is less science risk to this MIT approach but more technological risk. They are trying to accelerate the commercial use of high-temperature superconducting magnets and trying to contain their costs. Cost for superconducting magnets for past fusion projects have been $20 per watt but other applications have seen costs of $1.4 to $1.8 per watt.

They want to mass-produce superconducting magnets that are 2X the field strength of past strong magnets while bringing the cost per watt down.

The list of items below that Commonwealth fusion is targeting is from 2018.

There are 16 subsegments stacked for each magnet and 18 magnets are needed for the demo net gain system.

Commonwealth Fusion has more detailed project plans and peer-reviewed papers indicate the science is sound.

SPARC will use new high temperature superconducting (HTS) magnets to enable a similar performance as ITER but built more than 10 times smaller and on a significantly faster timeline.

The papers also predict that SPARC will very likely achieve a burning plasma for the first time on earth, meaning the fusion process will be dominantly self-heating. This is a major multi-decade goal of the world’s scientific community. In 2020, Commonwealth Fusion Systems (CFS) had a series of seven papers published and peer reviewed in a special edition of the Journal of Plasma Physics validating CFS’ approach to commercial fusion energy.

NOTE: Two years ago Tokamak Energy reported progress on a 20 Tesla magnet.The Commonwealth Fusion System 20 Tesla magnet is more complete for a fusion project. There are also more powerful magnets at the National Magnet lab. There is a 32 Tesla superconducting magnet. 42 Tesla hybrid magnet and 100 Tesla pulse magnet. Those magnets are for lab work and would be suitable for the Tokamak project.

SOURCES – Commonwealth Fusion Systems, Journal of Plasma Physics
Written By Brian Wang,

32 thoughts on “Billionaires Put $2 Billion into Commonwealth Fusion Systems”

  1. Hey, I know this question is only tangentially related to fusion energy (via the whole greenhouse gases from energy production angle) but:

    Since 1850, CO2 has risen from 290ppm to 400ppm.
    N2O has risen from 270ppm to 335ppm.
    +110ppm and +65ppm, respectively.

    But N2O has a greenhouse warming potential 275x that of CO2 over the same period.
    So the N20 impact would seem to be 65×275=17875ppm CO2 equivalent impact.
    That is 162.5 times as big an impact on warming as the actual 110ppm increase of CO2.

    Am I misunderstanding something here? Because until recently all the focus has been on CO2 and to a lesser degree methane, and I’ve seen almost nothing about N2O until the past couple days, with the Netherlands farmer protests.

  2. I hope it works. Now, if you guys succeed with this approach, and l hope it does, this may enable most third world countries to use this ultimate source of energy. As it is now, the current approach being applied, as in the ITER project, most likely will not be affordable to most of these less advanced and poor countries. Is there anything ongoing to address this issue to provide such countries the necessary means to use fusion energy? Thank you.

    • Nuclear fusion is a new energy approach with technological and scientific uncertainty. Any near-term to mid-term energy planning should be with proven energy solutions. nuclear fission, solar, wind, natural gas, hydro, coal. If coal and natural gas are used then the pollution will have to be managed.

  3. Typical fusion nonsense. Can’t solve the micro-instability problem? Let’s just make a stronger magnet and call that an advance.

  4. This project is great at employing physicists and generating headlines, but if you actually want to produce power, why struggle with hydrogen, when uranium works, literally, by being put in a pile? No magnets that could lift 400 747s needed. Instead of having a ten-second pulse as the goal, you have designs now operating that can run for thirty years without refuelling.

    • Because fusion fuel is more common than uranium in the solar system and interstellar colonization will be easier with fusion.

      • Fission fuel costs are a fraction of the cost of a nuclear power plant. From an economic perspective it doesn’t make much of a difference if the fuel is fission of fusion fuel.

      • Summer child, if some radioactive species live for a million years, they are so minutely weak that you might be more irradiated by eating a banana than by living in a house made of the stuff. The worst offenders in the Chernobyl disaster, for reference, are Cesium-137 and Strontium-90, both with half-lives of around 30 years, are the main long-term concerns with radioactive fallout. But these can be dealt with simply by keeping them inside the reactor where they will absorb more neutrons and in turn transmute into more quickly-decaying species which will soon decay into eventually stable products inside the reactor itself.

      • They’re not ‘waste’, they’re ‘partly used fuel’. If our descendants haven’t figured out how to use them within one generation, let alone hundreds of thousands, I’d be very disappointed with them. The energy content of uranium 238, which makes up about 95% of ‘spent’ fuel, would be far more valuable than an equal amount of gold. Fast reactors, that could use it, already exist, and more are being built.

    • In a Tokamak, the strong magnetic fields confine the hot plasma so it doesn’t touch the physical walls. Some heat does end up in the walls, but they have cooling channels to limit the temperatures. In a power reactor the cooling system will produce steam, to run a generator.

      • Heh heh. The devil is in the details. Were that the case, fusion should have happened 4 decades ago. We don’t really know how to control the 4th state of matter.

        • We can control plasma just fine and have an excellent understanding of it. See for example the stellarator wendelstein 7-X.

  5. Yes, I am a grammar enthusiast. Almost stopped reading this article when the writing quality problems appeared.

    “ at ten times lower cost“. ???

    “ reactor 40 times smaller“ ???

    Really ? WTF is that ? Where is the copy editor ?

    • It is a blog and there is no copy editor. Deal with it. Some people read blogs for educated insight in to future technology, some people read other blogs for punctuation and grammar, and some people read blogs for the witty comments.

  6. Do any other industries have a use for these magnets?

    Fusion is a great goal and all, but businesses that make money doing more than one thing tend to last longer. Maybe last long enough to achieve their primary goal.

    • Agreed, but look at the Wright Brothers airplane. It barely worked, but proved to the world that heavier than air flight was possible. That is exactly what the world needed for countries to pour more money into their own research. Within 30 years of that breakthrough, we had many of the finest piston driven airplanes to have ever taken the skies.

    • General Fusion has the advantage that the entire reaction takes place in a void in a vat of molten lithium-lead that both absorbs neutrons and breeds more tritium.


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