If scaled up, DOE Milestone program could truly catalyze fusion energy
Today, Commonwealth Fusion Systems (CFS) announced we’ve finished manufacturing and rigorously testing a key component for our SPARC fusion machine — a superstrong superconducting magnet that’s blazing the trail to commercial fusion energy.
The magnet didn’t just pass our own tests, a monthlong workout under SPARC operational conditions. Through its Milestone-Based Fusion Development Program, the US Department of Energy independently validated the magnet’s performance: We built a production version of this magnet, not just a prototype. And passing the DOE evaluation unlocked an $8 million Milestone award.
This achievement gives a taste of the Milestone program’s full potential — if it’s scaled up significantly.
DOE’s Milestone program is a key enabler for commercial fusion, not just for us at CFS, but also for our industry. We’d like to see a larger Milestone program, though. That could be as big a deal for the future of fusion power as a similar NASA program was for successfully building the US commercial space industry.
Here, we’ll explain why.
How DOE’s Milestone program speeds fusion progress
In a nutshell, milestone-based programs can efficiently support the creation of industries.
Once a national need is identified — fusion power plants that promise clean, abundant, secure, safe energy, for example — milestone programs offer a step-by-step way to accelerate their progress with minimal risk to the taxpayer. Unlike how traditional grant programs work, milestone payments are only made after the milestone is achieved.
In DOE’s Milestone program, companies and the government agree ahead of time on milestones the companies need to meet to prove out their fusion power plant technology and on appropriate fixed-price awards for reaching those milestones. CFS is funding more than two-thirds of the cost of its group of milestones in this current, first phase of the program.
The DOE Milestone program offers benefits to participating companies and to the government:
- Robust scrutiny validates each company’s overall commercial pathway and the specific technical milestones on that pathway.
- Companies receive financial support as they prove out their technology. That they can invest that funding into work on their next milestone.
- Milestone validation and support can unlock new private capital for the companies. At the same time, the Milestone program can leverage private capital that’s already been raised.
- Risk to the US government is tightly constrained: DOE doesn’t pay if a company doesn’t achieve the milestone.
- If it costs a company more than than expected to achieve a milestone, the government still only pays the fixed, agreed-upon amount, while the company pays the extra. Similarly, if the company achieves the milestone later than expected, the government doesn’t pay until it’s done.
- The program supports the nation’s National Laboratories and universities. CFS has contracted with Oak Ridge National Laboratory, Princeton Plasma Physics Laboratory, MIT, and Columbia University to contribute to our Milestone program work.
Ultimately, with the Milestone model, the benefits of fusion energy — a secure, clean, safe, dispatchable source of electricity — can arrive on the grid sooner.
More Milestone funding could help match NASA’s success
The DOE Milestone effort is modeled after a similar, highly successful program, the NASA Commercial Orbital Transportation Services (COTS) program. It turned relatively modest federal investments into private-sector abilities to carry cargo and crew to the International Space Station. That not only restored an ability the US had lost with the end of the Space Shuttle program, but also led to a new, thriving commercial space-launch industry.
COTS was a financial home run for NASA and the nation.
NASA invested $788 million in the COTS program in total — $500 million in fiscal 2006 and $288 million in fiscal 2011, which adjusted for inflation totals $1.2 billion in today’s dollars. That more than paid for the economic activity that COTS enabled: the US space industry is a $143 billion annual market today, according to the Bureau of Economic Analysis. By helping to build a thriving space launch business COTS also spurred entirely new industries like Starlink’s satellite-based broadband.
Fusion energy promises to be a similarly enabling technology.
So far, only a fraction of the $415 million Congress authorized to carry out DOE’s Milestone program has been appropriated. We’d like to see DOE not only fully fund all three phases in this part of the Milestone program, but also to expand it to accelerate the construction of fusion power plants through a demonstration phase. That would support the private sector’s competitive engine in the US, strengthening our nation’s energy security and economic growth.
How DOE Milestone program has worked so far
DOE’s Milestone program began by selecting the fusion energy companies. For the first phase of the program that’s underway now, DOE chose CFS and the seven others in 2023. After that selection, the companies negotiated with DOE to agree on their commercially relevant milestones and an appropriate reimbursement.
Next comes the execution and the scrutiny. When a company achieves a Milestone, a DOE expert panel reviews the company’s completion report. This panel assesses the report against predefined criteria to either approve or disapprove Milestone completion and reimbursement.
In this case, the Milestone award supported our work to manufacture and test for acceptance a production toroidal field (TF) magnet at our facility in Devens, Massachusetts, and confirms that our magnet has passed performance tests required to ensure it’ll work in SPARC.
Both our own TF testing and the Milestone scrutiny were serious. A battery of tests put the magnet through its paces under the conditions it’ll face inside SPARC, with high electrical current, strong magnetic fields, and powerful physical forces.
Then DOE’s panel of independent experts carefully evaluated our tests and results. That panel included subject matter experts with peer-reviewed papers and decades of experience in areas like magnet technology, particle accelerators, and materials science — including people who have built their own high-field magnets. That level of rigor is required to ensure the Milestone program delivers the full value of its validation.
The $8 million DOE award for the TF magnet is about half of the $15 million we’re eligible to receive from DOE in this part of the Milestone program — the first of the program’s three planned phases.
It’s our third Milestone achievement. CFS already received $1.7 million for applying for our radioactive materials license from the Commonwealth of Massachusetts (which we’ve now received) and for work with local communities and supporting workforce development.
CFS reaches a tokamak magnet milestone
Our TF magnet, the largest high-temperature superconducting magnet and nearly twice as strong as the previous generation of technology, is one of 18 at the heart of our SPARC fusion machine. That strength means our fusion devices, called tokamaks, can be more compact and economical so fusion energy can spread far and wide. You can see one of these magnets under construction in the photo at the top of this post.
Our TF magnets are designed with a novel technology called non-insulated non-twisted (NINT) that’s central to the CFS mission to deliver fusion energy, at scale, as soon as possible. It enables magnets that are more compact and easier to manufacture than the cable-based magnets elsewhere in our tokamaks. And those steel plates are strong, a key attribute.
SPARC will be the world’s first commercially relevant machine to demonstrate net fusion energy. It won’t make electricity, but it will show that the heart of our power plant can make grid-scale power. We’re building it now at our headquarters to pave the way for our later ARC fusion power plant.
When DOE’s independent review process chose CFS for the Milestone program, it sent a signal to investors, researchers, governments, and others watching fusion that our technology provides a realistic pathway to commercial deployment. Our production TF magnet now passing that test sends an even stronger signal of credibility.
We still have plenty of work ahead to finish SPARC and then design and build its ARC power plant successor. But the Milestone program is an important tool to break those big projects into smaller steps, providing the incentives that help us take them as fast as possible.
SPARC® and ARC™ are trademarks of Commonwealth Fusion Systems®.
