JASON Panel reviews ARPA-E Fusion Effort
January 27, 2019
In 2014 the US Department of Energy ARPA-E initiated a three-year $30M
program called ALPHA to explore magneto-inertial fusion (MIF) concepts
in a range of plasma density lying between the magnetic confinement
(lower density) and inertial confinement (higher density) approaches to
fusion. ALPHA's goal was to identify ways to accelerate progress toward
fusion power. With the ALPHA program nearing completion, ARPA-E asked
JASON (a prestigious scientific panel) to assess its accomplishments
and the potential of further investments in this field. JASON members
listened to two days of briefings that included participants in ARPAE's
ALPHA program, MIF teams not supported by ALPHA-E, and teams working on
pure magnetic confinement fusion. JASON also surveyed nine teams for
quantitative metrics of past, present, and projected progress along
critical physical parameters. Their report, titled "Prospects for Low
Cost Fusion Development" was completed in late November 2018, The
Executive Summary is provided below.
Controlled thermonuclear fusion has been pursued for more than 60 years.
In recent decades, US funding has focused on laser-driven inertial
confinement (ICF) for national security purposes and on magnetic
confinement (MCF), primarily in tokamaks, for energy production. The
major component of the latter international program is the $25B ITER
project, expected to begin DT operation in 2035.
The findings of this study are summarized as follows:
These findings lead to the following recommendations:
- Magneto-Inertial Fusion (MIF) is a physically plausible approach to studying controlled
thermonuclear fusion in a region of parameter space that is less explored than Inertial
Confinement Fusion (ICF) or Magnetic Confinement Fusion (MCF).
- MIF research is immature. Despite having received ~1% the funding of MCF and ICF, MIF
experiments have made rapid progress in recent years toward break-even conditions, and
some (e.g. MagLIF) are within a factor of 10 of 'scientific break-even'.
- There are many plausible and distinct approaches to MIF. Some early projects supported by
the ALPHA program are showing rapid progress in critical physical parameters and have not
yet reached insurmountable obstacles. As in ICF and MCF, instabilities may make scientific
break-even MIF more challenging than simple scaling estimates suggest.
- ALPHA program support for development of broadly applicable technologies has accelerated
progress of multiple efforts. All MIF approaches would benefit from improved understanding
of plasma instabilities and liner-plasma interactions, better computational tools, and
- While scaling from current experiments is uncertain, it is likely that reaching scientific breakeven
with a single MIF prototype will cost at least several $100M and possibly much more.
Considerably larger expenditures would be required to go from scientific breakeven to a
demonstration power plant; and even more from a demo to a production capability.
- Given the immaturity of the technologies, the future ability of fusion-generated electricity to
meet commercial constraints cannot be usefully assessed. Rapidly developing infrastructures
for natural gas and renewable energy sources and storage will compete with any future
commercial fusion efforts. Nevertheless, there is a small but growing private-sector
community investing in and pursuing commercial fusion projects.
- The pursuit of MIF could lead to valuable spinoff technologies, and to non-power fusion
applications, with broad civilian and military import. Some approaches have low enough
mass to be candidates for space propulsion, but it is too early to impose the relevant design
constraints (low weight, low thermal dissipation) on ongoing research.
- MIF research could productively absorb a significantly higher level of funding than the
$10M/yr of the ALPHA program.
- MIF activities should be supported by an investment in basic research to:
- study plasma instabilities and transport under MIF conditions, and
- study plasma-liner interactions.
- The National Laboratories should contribute their unclassified state-of-the-art simulation
codes to collaborations with academic and commercial efforts, and support training of
- Targeted technology development programs should focus on development of components,
including plasma guns (high Z and low Z), pulsed power and electronics, diagnostics, and
advanced magnets and materials.
- The near-term goal should be scientific break-even (thermonuclear energy out > mechanical
+ electromagnetic energy into the fuel) in a system that plausibly scales to a commercial
plant. Until that goal is achieved, set aside questions of neutron economy (tritium breeding)
or balance of plant. Pursue system integration only insofar as it is needed to demonstrate
- Explore pulsed neutron sources and space propulsion as motivating applications with
different constraints than grid electricity. Efforts in these speculative directions should
supplement, not replace, basic MIF research.
- Support all promising approaches for as long as possible. Do not concentrate all resources
on early front runners.
Copies of the full report are available at:
The full report contains the following addendum as commentary on the report by ARPA-E:
ARPA-E is grateful to JASON for conducting this study and for their
insightful findings and recommendations.
Here, we provide commentary related to their finding #6: "Given the
immaturity of the technologies, the future ability of fusion-generated
electricity to meet commercial constraints cannot be usefully assessed..."
This is a fair statement given the large uncertainties in the state of
the technology and in the future needs of the U.S. and world electricity
markets. However, in the view of ARPA-E, some of the analysis in Sec.
2.3 (Fusion in the Energy Landscape) does not adequately capture the
full range of potential outcomes for either the technology or for the
Section 2.3 includes some analysis based upon a maximum
levelized-cost-of-electricity (LCOE) of $0.05/kWh, which is drawn from
the current estimate for natural gas combined cycle (NGCC) electricity
generation, and leads to a rough estimate of a maximum allowable
overnight capital cost of $5.55/W. This is compared against a notional
$6.67/W fusion power plant from the referenced Bechtel cost study.
However, the latter, which examined the cost drivers for four
fusion-core concepts applied to a 150-MW point design, was intended to
identify the main cost levers, not to arrive at accurate, absolute
capital cost estimates for a future fusion plant. In fact, the study was
based upon costing models for nuclear fission plants that are already
known to be well above costs being achieved in other parts of the world.
For example, Korea has repeatedly shown that present-generation fission
plants can be built for roughly $2/W. Thus, conclusions drawn based on
capital cost estimates from the Bechtel study could be overly
From the standpoint of market needs, a benchmark of NGCC in the current
context of the U.S. grid does not adequately capture global markets
and/or market segments where fusion might be first adopted, or the
future needs of the electric grid. Benefits of fusion that do not factor
into such an analysis include:
- minimal carbon emissions
- geographic siting flexibility, with a small footprint, including near dense population centers
- seasonal stability, high dispatchability, and potential load-following capability
- a practically inexhaustible fuel supply with minimal need for new transportation/delivery infrastructure.
In fairness, NGCC does address some of these considerations as well, but
these features are not well captured by the $0.05/kWh LCOE figure. The
JASON study does note that there are applications that can justify
electricity costs well above the notional $0.05/kWh, and that the likely
largest market for fusion energy may not be in the U.S. In addition, the
study acknowledges that there are certain markets within the U.S. where
there are income streams for ancillary services that can meet or even
exceed the value of selling baseload electricity. These caveats serve to
remind us that directly comparing early estimates for fusion-plant
capital costs with income based on current U.S. LCOE projections for
NGCC is too restrictive to assess the future market attractiveness of
Beyond the specific details of the cost analysis, the JASON report
highlights the importance of including cost analyses in assessing the
potential real-world impact of fusion (or any energy technology). This
is a message that ARPA-E appreciates, and we hope that the fusion R&D
community will embrace this attitude as it continues to make progress.