Month: September 2025

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Small Modular Reactors: Betting the Grid or Hedging the Odds?

Small modular reactors (SMRs) have been heralded for more than a decade as the next big breakthrough in nuclear power — compact, factory-built reactors that can be deployed faster and more cheaply than the megaprojects of the past. Advocates claim they will provide reliable, zero-carbon baseload power that balances renewables. But a fundamental question remains: what are the odds that SMRs will actually be economically viable in the United States by 2035?

Economically viable means:

· Repeatable build time ≤ 5 years from decision to invest in a project;

· All-in LCOE ≤ $70–90/MWh (firm, dispatchable);

· ≥ 2–3 GW of firm orders (not just MOUs), i.e., commercial traction beyond one First of a kind (FOAK).

To answer that, we applied a Bayesian framework: begin with a prior assumption about the likelihood of success, then update that probability as new evidence is introduced. The calculation involves the following equation:

Odds of achieving question = Guess of odds without further evidence x (likelihood ratios for each element of new evidence, multiplied together)

Starting Point

We began with a neutral 50% prior probability that SMRs will succeed — essentially a coin toss. This reflects the “hype vs. skepticism” balance in the public debate, without assuming either optimism or pessimism.

From there, we assessed each of five leading U.S. developers — GE Hitachi, NuScale, TerraPower, X-Energy, and Kairos — and applied likelihood ratios based on four evidence categories:

  1. Licensing familiarity (light-water vs. advanced designs)
  2. Fuel availability (conventional uranium vs. HALEU)
  3. First-of-a-kind delivery risk (track record on cost and schedule)
  4. Financing and policy support (access to capital and federal backing)

Updating the Odds

GE Hitachi (BWRX-300):

  • Strong NRC pathway, multiple international projects, conventional fuel.
  • Posterior probability: ~20–25%.

NuScale (VOYGR):

  • NRC-certified, but credibility hit by canceled Utah project and rising costs.
  • Posterior probability: ~6–8%.

TerraPower (Natrium):

  • DOE- and Gates-backed, but dependent on HALEU and unproven sodium cooling.
  • Posterior probability: ~6–7%.

X-Energy (Xe-100):

  • Pebble-bed design with DOE support, industrial heat niche, but HALEU-dependent.
  • Posterior probability: ~5–6%.

Kairos:

  • Very early stage, novel salt-cooled approach, highest technical and fuel risk.
  • Posterior probability: ~2–3%.

Aggregate Outlook

When combining across all five players, the probability that at least one company delivers an economically viable SMR by 2035 comes out to:

  • Planning Case (balanced assumptions): ~33–40%
  • Conservative Case (heavier weight on FOAK and fuel risks): ~20–25%
  • Optimistic Case (favorable licensing and supply chain development): ~45–50%
  • Base Case (all evidence considered at current weightings): ~8–10%

So, while the starting point was a coin flip, the evidence pushes the odds downward.

Why the Probabilities Matter

  1. Fuel bottleneck: Three of five contenders rely on HALEU fuel, which has no established commercial U.S. supply chain. Without it, those designs are stuck.
  2. Licensing realities: Light-water SMRs (GEH, NuScale) are advantaged, but even they face long NRC timelines and FOAK delivery risk.
  3. Financing risk: Private capital remains wary until a second or third unit demonstrates on-time, on-budget delivery.
  4. Competing technologies: Solar, wind, and storage costs keep falling, raising the bar for SMR competitiveness.

Policy Implications

  • Policymakers should treat SMRs as a hedged option — worth monitoring and supporting at the R&D and demo level, but not as a guaranteed pillar of decarbonization.
  • Long-range resource planning should assign low-to-moderate probability weightings to SMRs becoming competitive by 2035.
  • The near-term focus should remain on proven tools — renewables, storage, demand flexibility, and transmission — while maintaining optionality for nuclear if credible evidence emerges.

The Takeaway

Using these assumptions, by 2035, there is at best a one-in-three chance that a U.S. SMR will prove both technically and economically viable. Among the contenders, GE Hitachi’s BWRX-300 stands out as the most credible, while others face steeper hurdles.

The Bayesian math underscores what intuition already suggests: SMRs are possible, but far from certain. Betting the grid on them would be a gamble; treating them as a long-shot option while focusing on proven, scalable solutions is the prudent play.

Of course, it’s all about the assumptions. Spreadsheet for this calculation available on request.

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Anti-Science Policies Threaten Our Health — and Our Energy Future

(updated 9/24/25)

Robert F. Kennedy Jr.’s views on medicine have garnered considerable attention since he assumed leadership of the Department of Health and Human Services (DHHS). Public health experts warn that implementing his anti-science views on vaccines and autism, as well as the elimination of vital research, will create a national health emergency. They’re right to be alarmed. Unfortunately, RFK Jr. is not the only ideologue appointed by the White House. Department of Energy (DOE) Secretary Wright is also promoting policies inconsistent with established science and technology, and Mainers are not immune from their consequences.

Secretary Wright and the outsiders he has brought into DOE, as well as the President himself, have made public statements and issued reports divorced from modern science and the current state of energy technology. DOE recently issued two reports that have come under considerable criticism. One was a bizarre compendium of all the climate science denier cliches of the last 20 years. The other, regarding grid reliability and power sources, was directly at odds with our current understanding of optimum operation of electricity grids and role of clean energy sources. Instead of listening to its own experts, DOE promotes an energy policy right out of the Nixon administration centered on building large fossil power plants to meet unrealistically high projections of demand, expecting just over the horizon nuclear plants to deliver power too cheap to meter.

Proposed transmission lines that better distribute power regionally have been blocked, expensive coal plants scheduled for retirement are being kept open, measures that make far better use of our existing power lines are ignored, and new energy sources that reduce the cost of power are being eliminated. The consequences of these disastrous policies are painfully clear: higher electricity bills, a less reliable grid, and increasing environmental costs.

The playbook is familiar: sideline the experts, replace facts with pseudo-science, and repeat myths until doubt sets in. The tobacco industry used this strategy to deter anti-smoking campaigns. Climate deniers have used it for decades. And now we see it in federal agencies.

But repetition gives these myths staying power. Just as RFK’s DHHS entertains unsubstantiated theories about medicine, DOE has opened its doors to an ideology that only fits politically selective perspectives. Once ideology drives the agenda, it is challenging to pull policy back to evidence, and ordinary Americans pay the price.

Many of these federal false narratives about energy are being echoed for adoption here in Maine, and Mainers can’t afford them. Every state in New England faces high electricity prices – driven not by renewable energy, but by reliance on expensive natural gas and delays in building grid infrastructure. Should the DOE’s mythologies make their way into Maine’s energy policy, we will all be worse off.

That’s why Mainers must be alert to disinformation coming out of Washington and repeated here at home. When you hear claims that renewables can’t keep the lights on and drive up costs, that accepted forms of utility regulation and rate design are political scams, or that climate change is exaggerated, remember these are not facts. They are the energy equivalents of denying the efficacy of vaccines or promoting unsupported theories about autism causes and cures.

The answer isn’t complicated. It’s a fact, not ideology, that adding clean sources of power and storage, along with modernizing the grid and enacting regulatory reforms, are the cheapest and cleanest ways to run our economy and make our grid more reliable.

When we ignore science in health, people get sick. When we ignore science and technology in energy, people pay more, suffer more outages, the economy falters, and the climate crisis worsens. Either way, families carry the burden.

We cannot let ideology replace evidence in health or energy policy. Maine deserves leaders who will stand up for facts over fiction, solutions over soundbites, and evidence over ideology. Whether it’s our health or our electricity, science-based policy isn’t just the smart path forward. It’s the only path.