Milestone-Based Fusion Development Program

The Milestone-Based Fusion Development Program is an ongoing program under the United States Department of Energy, office of fusion energy sciences to support the development of a fusion pilot plant (FPP) and eventually commercialize fusion power. As of 2024, eight private companies have received a total of $46 million for the first 18-month period of performance. The program is planned to run for five years and culminate in one or more fusion pilot plants.

The need for a fusion pilot plant has been recognized throughout the program to develop fusion power. Most recently before the announcement of the Milestone-Based Fusion Development Program, in 2021 the National Academies of Sciences, Engineering, and Medicine (NASEM) released a report which highlighted the need for such a program and advised its creation. In 2022 the Biden administration and DOE announced a Bold Decadal Vision for Commercial Fusion Energy which included plans to fund support for pilot plant development program.

The funding opportunity announcement (FOA) was announced by the US Department of Energy in September 2022, and $50 million was earmarked for the program. Applications were received in December 2022. Eight companies were selected for negotiation in May 2023. However, agreements were not signed with the awardees until more than a year later in June 2024, reportedly due to concerns over how intellectual property would be handled.

In June 2024, at a White House summit the Department of Energy announced that all eight companies had successfully concluded detailed milestones negotiations with the federal government and that agreements had been signed to commence the Milestone Program.

The eight awardees are:

• Commonwealth Fusion Systems (Cambridge, MA)
• Focused Energy Inc. (Austin, TX)
• Thea Energy, Inc (formerly Princeton Stellarators Inc., Branchburg, NJ)
• Realta Fusion Inc. (Madison, WI)
• Tokamak Energy Inc. (US subsidiary of UK-based company, Bruceton Mills, WV)
• Type One Energy Group (Madison, WI)
• Xcimer Energy Inc. (Redwood City, CA)
• Zap Energy Inc. (Everett, WA)

The awardees include 2 companies pursuing the tokamak approach, 2 companies pursuing the stellarator approach, 2 companies pursuing inertial confinement fusion, one company pursuing the magnetic mirror approach, and one company pursuing the Z-pinch approach.

The program is structured as a public–private partnership between the DOE and the awardees. The companies unlock matching funds upon completion of quantitative milestones, up to the full award amount.

The program is structured in three periods of performance: One spanning the first 18 months, one spanning the second 18 months, and one spanning the remaining 24 months of the five-year term. The first period of performance will presumably end around the end of 2025, assuming a start date based on the June 2024 announcement.

Only the first period of performance has been announced and awarded. The $46 million number is for the first period of performance. Subsequent periods of performance have not as of 2024 been announced, appropriated, or awarded.

The applicants were encouraged to propose collaborations with US national laboratories, with which the DOE would contract separately and pay directly. Oak Ridge National Laboratory will work with six of the eight companies.

As of January 2025, the DOE has announced that at least 3 companies have completed at least 5 scientific and technical milestones. While the specific milestones are typically protected information of the company, the following were announced. There may be more milestones that have been completed:

• Computational modeling for a high-gain target design for laser-driven inertial fusion energy (Focused Energy)
• Demonstration of ion-beam focusing to support fast-ignition approach to inertial fusion energy (Focused Energy)
• Whole-device modeling of simple mirror equilibria to enable scientific energy gains of at least 5 for the tandem-mirror approach to fusion energy (Realta Fusion)
• Down selection to a family of optimized stellarator equilibria taking into account multiple factors of plasma confinement, stability, and stellarator components and subsystems (Thea Energy)
• Engineering design, prototyping, and operation of a single, high-temperature-superconducting magnet coil that is the building block of Thea Energy's approach to generating 3-dimensional, optimized stellarator fields using only planar coils (Thea Energy)

The year-long gap between the announcement of awardees and their signing agreements with the DOE was apparently due to a dispute over how companies' intellectual property would be treated under the award. Reporting stated that the companies' rights to existing and subject intellectual property was not sufficiently safeguarded under the DOE's initial proposed terms. At the time of the announcement, the total private investment in Commonwealth Fusion Systems was larger than $2 billion.