References & Methodology

Full source list for every fact, figure, and indicator in the Fusion Energy Progress Dashboard.

Last comprehensive fact-check: 28 March 2026

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Methodology & General Caveats

How this dashboard is compiled: All data is sourced from publicly available information including official project websites, peer-reviewed publications, government reports, industry surveys (primarily the Fusion Industry Association annual report), news coverage, and company press releases. Data was last comprehensively fact-checked in March 2026.
General Caveats for All Data:
  • Funding figures are company-reported and may include milestone-tied commitments, SPAC valuations, or stock deals. Actual capital deployed may differ significantly from headline numbers.
  • Projected dates are aspirational targets set by companies or governments, not independent predictions. The historical track record of fusion timelines is very poor.
  • Progress stages (0-7) are editorial assessments by this dashboard, not self-reported by companies. Reasonable people may disagree on stage assignments.
  • Confidence assessments (high/medium/low) are subjective editorial judgements, not statistical probabilities.
  • Cost estimates for fusion power plants are highly speculative — no fusion power plant has ever been built or operated.
  • Temperature claims vary by measurement method (ion vs electron temperature) and are not always directly comparable across devices.
  • Government spending figures are estimates from public sources. Many governments (especially China) do not publish consolidated fusion budgets.
  • "Net energy" terminology is frequently conflated: target gain (energy into target vs out), physics Q (heating power vs fusion power), and engineering Qe (wall-plug electricity in vs out) are fundamentally different metrics.

Sections

ITER Commonwealth Fusion Systems (CFS) / SPARC Helion Energy TAE Technologies Tokamak Energy General Fusion First Light Fusion Zap Energy Type One Energy NIF / LLNL EAST / CFETR (China) KSTAR (South Korea) JT-60SA (Japan/EU) STEP (UK) Marvel Fusion Wendelstein 7-X Viability Signals Key Assumptions Waste & Safety Funding Landscape Timeline Scenarios Feasibility Scores

ITER

Caveat: ITER cost figures are contested. ITER's own budget accounts for ~EUR 22B. The US DOE estimates ~$65B including all in-kind contributions from member nations. The discrepancy reflects different accounting methodologies, not fraud. Both numbers are defensible depending on methodology.

Commonwealth Fusion Systems (CFS) / SPARC

Caveat: SPARC has not yet operated. All performance claims (Q>2, 140 MW fusion power) are projections from physics models. The 20T magnet was demonstrated and DOE-validated, but a full toroidal set has not been operated in a fusion device.

Helion Energy

Caveat: Helion originally targeted net electricity by 2024 — this was not achieved. The 2028 Microsoft PPA target remains extremely ambitious. 150M°C is ~75% of what Helion estimates is needed for their ultimate D-He3 fuel cycle. D-T fusion was demonstrated but net energy was not.

TAE Technologies

Caveat: TAE's ultimate p-B11 fuel target requires plasma temperatures of ~1 billion °C. Their current record is 75M°C (~7.5% of target). The 2031 grid target for Da Vinci is extremely ambitious. The $6B TMTG merger is an all-stock transaction, not direct R&D funding.

Tokamak Energy

General Fusion

Caveat: LM26 achieved first plasma and first compression, but has not yet reached 100M°C or scientific breakeven equivalent. These are targets, not accomplished milestones.

First Light Fusion

Caveat: First Light cancelled Machine 4 and pivoted to technology licensing in 2025. The FLARE concept's 1,000x gain is a model projection, not an experimental result. The company is no longer building its own power plant.

Zap Energy

Type One Energy

Caveat: The TVA letter of intent is a non-binding expression of interest, not a firm contract. No stellarator has achieved reactor-relevant conditions. The $250M Series B was not yet closed as of Jan 2026.

NIF / LLNL (National Ignition Facility)

Caveat: "Ignition" and "target gain" refer to energy delivered to the target capsule vs fusion energy out. NIF's laser is ~1% efficient, so the wall-plug energy input is ~200 MJ, making wall-plug Q < 0.05 even at 8.6 MJ yield. NIF is a weapons physics facility, not designed for power generation. It fires ~1 shot/day vs the ~10 Hz needed for a power plant.

EAST / CFETR (China)

Caveat: Temperature reports for EAST vary by source. Some report "over 100 million °C" and others "nearly 70 million °C" for the same shot — likely reflecting ion vs electron temperature measurements. Chinese fusion spending estimates are approximate as no consolidated public budget exists.

KSTAR (South Korea)

JT-60SA (Japan/EU)

STEP (UK)

Caveat: STEP targets net electricity by ~2040, but design approval is not expected until ~2032 with construction through the 2030s. No spherical tokamak power plant has ever been built. Funding beyond initial commitment may depend on future government decisions.

Marvel Fusion

Caveat: Nonthermal laser fusion is less validated than thermal ICF (NIF approach). The laser facility is under construction, not yet operational. EUR 215M of the total is public project funding which may carry milestone conditions. Experiments are not expected to begin until early 2027.

Wendelstein 7-X

Viability Signals

Caveat: Viability signal assessments (high/medium/low significance) are editorial judgements. Positive and negative signals are presented together to maintain balance, but readers should weight them based on their own assessment of the evidence.

Key Assumptions & Validation Status

Caveat: Confidence percentages on assumptions are subjective editorial estimates, not statistical probabilities. "Partially validated" means key aspects are demonstrated but critical gaps remain. The assumptions section reflects the state of knowledge as of March 2026 and will need periodic updates.

Waste & Safety

Caveat: Waste and safety comparisons between fusion and fission are based on physics and engineering analysis, not operational experience (since no fusion power plant exists). Actual waste volumes, activation levels, and decay times will depend on specific materials choices, neutron fluences, and plant designs that are not yet finalized. The "~100 years to clearance" estimate assumes use of low-activation materials (RAFM steels, SiC) which are still under development.

Funding Landscape

Caveat: Private funding figures are self-reported by companies. They may include milestone-tied commitments that have not been disbursed, SPAC valuations, or stock transactions (e.g., TAE's $6B TMTG merger). Government funding figures use different accounting methods across countries and are not directly comparable. China's fusion spending is particularly opaque.

Timeline Scenarios

Caveat: All timeline scenarios are editorial assessments, not forecasts. Probability ranges are subjective. The historical track record of fusion timelines is very poor — ITER alone has slipped ~18 years from its original first plasma target. Private company timelines have also historically slipped (e.g., Helion targeted net electricity by 2024). Readers should calibrate expectations accordingly.

Feasibility Scores & Critical Path

Caveat: All feasibility scores (0-10) are editorial assessments by the dashboard authors, not standardized metrics. Sub-parameter scores are subjective. Reasonable experts disagree significantly on engineering and economic feasibility assessments. The scores reflect a "honest middle ground" — neither promotional nor dismissive — but should not be treated as authoritative.

General / Cross-Cutting Sources

This references page was compiled as part of a comprehensive fact-check conducted on 28 March 2026.

Data and sources should be independently verified. Fusion energy is a rapidly evolving field — information may become outdated quickly.

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