Investment Risk Is Highest for Nuclear Power Plants, Lowest for Solar

Limits of LCOE and Cost Metrics

• Several comments note that simple LCOE charts (especially older ones) are misleading: they often ignore grid integration, variability, and timing of generation (“watts at night”).
• Grid costs for renewables (batteries, transmission, inertia provision) are often excluded from LCOE but are real and sometimes large.
• Others argue that even with storage and grid costs added, new nuclear is still more expensive than solar + storage, especially given rapid cost declines in renewables and batteries.

Grid Stability, Inertia, and Blackouts

• One side emphasizes the value of physical inertia from large turbines (nuclear, hydro, gas) and claims renewables need additional investments to replace that.
• Another side counters that modern inverters and batteries can provide synthetic inertia and grid-forming capabilities, making heavy rotating mass unnecessary.
• The cause of Spain’s Iberian blackout is disputed: some blame lack of inertia, others cite inverter misconfiguration or reactive power/overvoltage, and say inertia was not the key issue. The exact root cause is described as still unclear by some.

Nuclear Economics, Regulation, and Risk

• Many agree nuclear has very high construction risk: huge upfront capex, long build times, and frequent cost overruns.
• Disagreement over why: some blame “wildly over‑regulated” and opaque processes; others say the zero‑tolerance safety requirement and political risk justify strict regulation.
• There is a long sub‑thread arguing whether long plant lifetimes (60–80 years) materially improve nuclear economics once discount rates, early closures, and competition from solar are considered.
• Some promote federal financing or guarantees since private capital struggles with long, risky payback; critics see this as massive subsidy and poor use of public funds.

Waste, Liability, and Externalities

• Pro‑nuclear commenters say waste volumes are small, storage methods are known (pools, dry casks, deep geological repositories), and surcharges already fund decommissioning.
• Skeptics point out that no country is yet operating a permanent repository, and that accident liability is largely socialized (e.g., liability caps), unlike for many other sectors.
• Comparisons are drawn to fossil fuels: their externalities and cleanup are also heavily socialized, but nuclear is held to a higher standard.

Renewables, Storage, and System Design

• Strong view that solar and wind, coupled with large grids, batteries, pumped storage, and possibly hydrogen/syngas, can economically reach very high penetrations.
• Others stress that in high‑latitude, long‑winter or cloudy regions (e.g., Sweden), non‑dispatchable renewables need firm backup (hydro, gas, nuclear, or coal), and that backup costs are often not attributed to renewables.
• Debate over how much long‑duration storage (tens vs 100+ hours or even seasonal) is needed; some argue occasional fossil backup is acceptable during rare extremes.

Scale, Modularity, and Construction Risk

• Commenters highlight “diseconomies of scale”: very large projects (especially >1.5 GW nuclear) show systematically higher cost escalation.
• Solar and wind benefit from modular, repeatable components with factory learning curves; they can start generating revenue as they are incrementally built, reducing financial risk.
• By contrast, nuclear projects only earn once fully complete after many years, compounding financing and political risk.
• Small modular reactors are discussed as a way to capture similar modular benefits, but commenters note that regulatory frameworks and financing models have so far prevented their promised cost reductions.

Policy, Markets, and Carbon Pricing

• Several comments distinguish “investment risk” (cost overrun) from ROI or social value; nuclear might be risky to build, yet valuable for energy security and firm capacity.
• Others argue current market structures favor cheap gas peakers and ignore climate externalities; a sufficiently high and well‑designed carbon price would shift economics away from gas toward renewables (and possibly nuclear).
• There’s contention over subsidies: critics say nuclear survives only via large direct and indirect subsidies; others respond that renewables have also received substantial support but are now increasingly subsidy‑independent.

Social License, Aesthetics, and Public Perception

• Some see the paper and similar messaging as “green propaganda” and complain about land use impacts of solar and wind (e.g., removal of olive groves).
• Others respond that every energy source has externalities and that nuclear’s perceived risk is driven more by fear, historic accidents, and politicized narratives than by current safety statistics.
• Early plant closures (e.g., in Germany) are cited as “social licensing risk” that undermines long-term nuclear ROI in a way solar and wind rarely face once built.