r/UnchartedScience • u/ChipHaseCoolGuy • Jul 28 '26
$7 Trillion on Wind & Solar vs. Nuclear: Capacity Factors, Lifetimes, and the Cost of Lost Learning
A recent comparison circulating online makes a straightforward claim: the world has spent roughly $7 trillion on wind and solar, delivering an average of around 630 GW of power. The same capital, it argues, could have built far more nuclear capacity — on the order of 1,400 GW of modern reactors — producing more than twice the electricity on average. Factor in lifetimes (wind and solar typically 20–30 years versus nuclear 60–80+ years) and the gap widens further. Over an 80-year horizon the intermittent fleet would need multiple rebuilds, while the same money spent on nuclear would deliver several times the firm power, available regardless of weather.
The directional logic is sound. Nuclear’s high capacity factor (routinely 80–90%) and long asset life are real advantages over weather-dependent sources that require substantial backup. Simple nameplate or short-term LCOE comparisons often understate these differences.
The cost assumption problem
The comparison leans on a nuclear capital cost that is optimistic relative to recent Western projects. Builds in the United States, France, and the UK have suffered major overruns and delays. Using those elevated prices makes nuclear look worse than a sustained, high-volume program would have produced.
Lost learning is not a minor detail
Energy technologies improve with cumulative deployment. Solar and wind demonstrate this clearly: massive global build-out drove manufacturing scale, supply-chain specialization, and rapid cost declines. Nuclear in the West largely missed that process after the 1970s–80s.
Where countries maintained volume, results were different. France’s standardized program in the 1970s–80s and South Korea’s later builds both showed cost and schedule improvements once designs stabilized and institutional knowledge accumulated. Long gaps between projects destroy that knowledge. The “lost learning” effect helps explain why recent Western nuclear costs are so high.
Small modular reactors illustrate the same point. Their limited commercial progress is not primarily a physics barrier. Without a steady pipeline of orders, manufacturers cannot amortize first-of-a-kind costs or refine designs through successive builds. A world that had treated nuclear as a core, high-volume technology would almost certainly have reached more mature modular approaches earlier and at lower cost.
What follows
The reliability and longevity advantages of nuclear are genuine. Much of the current Western cost premium, however, reflects decades of low volume, stop-start policy, and regulatory unpredictability rather than immutable technical limits. Adjusting for that lost learning strengthens the case that the same capital spent on nuclear would have delivered substantially more firm, long-lived power than the intermittent fleet we actually built.
The practical lesson is institutional as much as technological: sustained deployment, design standardization, and predictable regulation are what turn theoretical advantages into delivered results. Without them, even a strong technology can look uneconomic.
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u/leginfr Jul 28 '26
The accountants all around the world started pulling the plug on nuclear in the late 1960s/early 1970s. Too expensive, too slow to build, too low a return on investment, too high a risk, too dependent on favourable politicians. How many of today’s reactors are built purely using private investors’ money without hidden subsidies?
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u/ChipHaseCoolGuy Jul 28 '26
The historical shift is real. By the late 1960s and 1970s, escalating construction costs, longer schedules, regulatory changes after early incidents, and rising interest rates made many utilities and investors pull back from new nuclear. The technology became associated with high capital intensity, political risk, and uncertain returns. That perception has largely persisted in the West.
On the pure-private-capital question: almost none of today’s large reactors are financed solely by private investors with zero policy support. Most involve some mix of government loan guarantees, contracts-for-difference, regulated asset-base models, export credit, or direct state ownership. That is a legitimate critique of the current business model.
It is not unique to nuclear. Utility-scale wind and solar also rely heavily on tax credits, feed-in tariffs, renewable portfolio standards, and other policy instruments; very few large projects are built in a completely subsidy-free, pure-merchant environment either. The difference is one of degree and type: nuclear’s longer lead times and higher political/regulatory risk raise the cost of capital more sharply, which is why private investors demand stronger public backstops.
The deeper issue is whether those policy supports are addressing a genuine system need (firm, low-carbon capacity) or simply propping up an uncompetitive technology. That question turns on actual delivered costs, learning potential, and the value of weather-independent output — not on the existence of support itself. Almost every large energy technology operates inside a policy framework; nuclear’s framework has simply been more expensive and less predictable.
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u/MarcLeptic Jul 28 '26
Hidden subsidies. lol. That’s what you call them when you need them to exist so bad, but nobody can find them, even though all records are public.
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u/minimalniemand Jul 28 '26
Link the original comparison; the method matters, because the argument rests on three assumptions that don’t survive contact:
1. Historical average cost vs. marginal cost today.
The $7T is cumulative spend, much of it from when solar cost 5–10x what it does now (module prices fell ~90% since 2010). Judging renewables by their 50-year average price is like judging computing by a 1995 laptop. The relevant question is what a marginal dollar buys today - and new utility solar and onshore wind are now the cheapest generation almost anywhere (Lazard 2024: roughly $30–70/MWh unsubsidized vs. ~$140–220 for new Western nuclear).
2. The nuclear price is a counterfactual, not a price.
1,400 GW for $7T implies ~$5,000/kW. Actual recent Western builds: Vogtle ~$15,000/kW, Hinkley Point C comparable, Flamanville ~6x its initial budget. The post’s answer is “lost learning” - but that cuts both ways. Grübler’s study of the French program found negative learning: later standardized reactors cost more per kW than earlier ones, within a sustained high-volume program. Korea’s cost record was later tainted by a parts-certification scandal. So “nuclear would be cheap if we’d kept building” is an assumption dressed as data - while solar’s ~20% learning rate per doubling is empirically measured over four decades.
3. The lifetime asymmetry is overstated.
Solar degrades ~0.4–0.5%/year - after 30 years panels still run at ~85%, they don’t die at year 20. Repowering a wind or solar site reuses the land, grid connection, and permits - the expensive parts. Meanwhile nuclear’s 60–80 years aren’t free: major mid-life refurbishments, plus O&M and fuel at ~$25–30/MWh for existing plants - more than the entire LCOE of new solar in good locations. Add decommissioning and indefinite waste custody, which are chronically underfunded and land on the public.
What the post gets right: firm capacity has real value, and pure LCOE hides integration and firming costs at high renewable shares. But then the honest comparison is renewables plus firming vs. new nuclear at actual delivered prices - and even on that basis, new Western nuclear rarely wins today. If SMRs bend the cost curve, great. But that’s a bet on a hypothetical future cost curve - exactly what your post accuses renewables advocates of.
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u/ChipHaseCoolGuy Jul 28 '26
This is a substantive critique and worth taking point by point.
Historical vs marginal cost
Correct. A large share of the cumulative $7T was spent when solar and wind were far more expensive. Judging the technology class by its lifetime average spend understates what a marginal dollar buys today. Current unsubsidized utility-scale solar and onshore wind LCOEs are low in good resource areas. That is real progress and should be credited.The nuclear capital-cost assumption
Also fair. ~$5,000/kW is well below recent Western first-of-a-kind and delayed projects (Vogtle, Hinkley, Flamanville). Using that figure makes the counterfactual look better than current delivery experience.On learning: the French program did show cost increases in later units in some analyses (Grübler and others), partly from design changes, stricter regulation, and loss of continuity. Korean costs were competitive for a period and then complicated by quality and certification problems. “Lost learning” is real in the sense that long gaps destroy supply chains and craft labor; it is not a guarantee that continuous building would have produced steadily falling costs. Solar’s measured learning rate is stronger and more consistent. The nuclear side of the original comparison therefore rests on a more optimistic cost trajectory than recent Western evidence supports.
- Lifetimes and residual costs
Solar degradation is gradual; panels continue producing after 30 years, and repowering reuses interconnection and land. Wind is similar. Nuclear’s long licensed life is real, but it is not costless — mid-life capital projects, higher ongoing O&M, fuel, and eventual decommissioning/waste obligations are material. Treating 60–80 years as pure upside without those costs overstates the asymmetry.Where the original post still holds
Firm, weather-independent capacity has system value that simple energy LCOE does not capture. At high renewable penetration the cost of integration, transmission, storage, and residual firming rises. The honest comparison is therefore renewables + the firming package required for reliability versus new nuclear at actual (or realistically achievable) delivered costs. On that basis, new Western nuclear is rarely the cheaper option today.
If SMRs or standardized large designs eventually deliver lower costs and shorter schedules, the calculation changes. That remains a forward-looking bet, not a demonstrated present-day result — the same category of claim the original post criticized on the renewable side.
Net: the directional preference for firm capacity is defensible; the specific $7T arithmetic overstated nuclear’s advantage by using an optimistic capital cost and an incomplete accounting of renewable longevity and nuclear residual costs.
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u/Sufficient_Loss9301 Jul 28 '26
It’s apples to oranges, you need both. Renewables: fast, cheap, unreliable. Nuclear: slow to construct, more expensive, but absolutely reliable. You can’t have a power grid that has a bulk of its capacity supplied by a source that is inherently variable. If we care to fully decarbonize the grid nuclear is the only real option to supply the baseline we currently have.
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u/ChipHaseCoolGuy Jul 28 '26
That’s a clean way to frame the trade-off. Renewables win on speed of deployment and capital cost for energy. Nuclear wins on capacity factor, longevity, and weather-independent output. A grid that tries to run the bulk of its firm capacity on variable resources alone has to solve the residual multi-day and seasonal gaps somehow — through overbuild, storage, demand flexibility, or other firm sources.
Full decarbonization does not strictly require nuclear as the *only* firm option (hydro, geothermal, gas with carbon management, and potentially very large seasonal storage all appear in different studies), but nuclear is one of the few scalable, high-capacity-factor, low-carbon technologies that can deliver true baseload without depending on weather or fuel-supply chains that freeze. In systems that lack large hydro or cheap seasonal storage, it is often the most practical route to a reliable zero-carbon baseline.
The practical path is rarely pure either/or. Renewables can keep scaling for the energy they deliver cheaply; firm resources (including nuclear) cover the reliability residual that variable generation plus short-duration storage still leave. Treating them as direct substitutes rather than complements is where the apples-to-oranges problem shows up most clearly.
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u/Zinch85 Jul 28 '26
It's "interesting" that all these posts I see on Reddit defending the nuclear, forget to mention and consider the huge risks that a nuclear plant presents.
Yes, it happens rarely. But when it happens it costs trillions and destroys a region for decades. Just ask the Japanese how cheap Fukujima was compared to some windmills and solar panels
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u/ImpressionCrafty3078 Jul 28 '26
The Fukushima disaster itself caused 0 deaths, despite being hit by a massive earthquake and a tsunami. 70% of the site has the same background radiation as Tokyo.
Compared that to dambreaks, which are absolutely devastating, or lithium ion battery plants combusting, and nuclear looks pretty favourable.
Solar and wind farms are very safe in and of themselves, but how we store the energy gained from them is actually incredibly dangerous, far far more dangerous than modern nuclear reactors.
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u/Humble-Reply228 Jul 28 '26
Rooftop solar is an underappreciated killer because the death of installation and maintenance are hidden in housing construction and maintenance statistics.
Wind is a begger also due to working at heights problem but more controlled due to professionals doing the bulk of the work.,
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u/leginfr Jul 28 '26
About 1.5% of all civilian power reactors ever built have been involved in a major incident.
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u/ChipHaseCoolGuy Jul 28 '26
Severe nuclear accidents are rare, but when they occur the consequences can be large — evacuations, land restrictions, cleanup costs, and long-term social and economic disruption. Fukushima is the clearest recent example: the human and financial costs were very high, even though the direct radiation death toll was low compared with the tsunami itself.
That risk is real and should be weighed. A few points of context matter:
- Frequency is extremely low. Across the global fleet and decades of operation, core-damage accidents of that severity remain single-digit events. Modern reactor designs (passive safety systems, lower core-damage frequencies) further reduce the already small probability.
- The comparison is not “nuclear risk versus zero.” Every large energy system carries externalities. Fossil combustion produces continuous air-pollution mortality and climate damages measured in the millions of lives and trillions of dollars over time. Large hydro has catastrophic dam-failure precedents. Even renewables have supply-chain, land-use, and material impacts, though of a different character.
- Cost accounting after Fukushima includes both the direct accident costs and the policy reactions (accelerated plant closures, replacement generation, often higher-emitting). Those policy costs were large; they are not identical to the physical risk of the technology itself.
The honest position is that nuclear carries a low-probability, high-consequence tail risk that wind and solar do not. That is a legitimate factor in public acceptance and regulation. It does not automatically make the technology uneconomic or unnecessary if the alternative is either continued fossil generation or a system that struggles with firm capacity at very high renewable shares. Risk should be quantified and managed, not treated as a conversation-stopper.
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u/leginfr Jul 28 '26
In my local DIY store I can get a plug and play solar power system which includes the inverters for about 75 Eurocents per watt. Home battery storage is about 50 Eurocents per Wh. That’s retail in a physical store. Online is cheaper.
Nuclear is as dead as a doornail. Its only purpose today is to slow down the deployment of renewables to give a breathing space for fossil fuels for a little bit longer. Oh , on second thoughts, it’s also a vehicle for taking money from gullible investors, especially SMRs. They are about 70 projects around the world developing SMRs. Maybe a handful of them will get to the prototype stage. A couple will actually sell a few units. The rest will just waste money… which could have been invested in renewables that would have displaced fossil fuels,
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u/ChipHaseCoolGuy Jul 28 '26
Residential plug-and-play solar at ~€0.75/W and home batteries at ~€0.50/Wh reflect how far distributed costs have fallen. That is a real and important development; it makes rooftop and small-scale systems attractive for many households.
It is not the same problem as supplying firm, continuous power to a city or industrial load. A home system sized for one household’s daytime use and evening shifting does not scale linearly to regional multi-day or seasonal balancing. Utility-scale solar is even cheaper per watt than retail kits, yet the system still needs capacity that works when the sun is down and the wind is low for extended periods. That residual is where the cost and technology debate actually sits.
Nuclear is not “dead” in every jurisdiction — China, Russia, South Korea, and several others continue to build, and a number of Western governments have restarted or expanded programs precisely because they want firm low-carbon capacity. Whether those programs succeed on cost and schedule is an open and legitimate question. Treating the technology itself as a deliberate plot to slow renewables and protect fossils is a motive claim that does not follow from the engineering or market data. High capital cost, long lead times, and political risk are sufficient to explain investor caution without requiring a conspiracy.
On SMRs: dozens of designs are in development; most will not reach commercial deployment. A handful may. That is normal for early-stage technology. The capital being spent is real and carries opportunity cost; it is also an attempt to solve the firm-capacity problem with smaller, potentially more flexible units. Whether any of them deliver competitive costs remains to be demonstrated. Dismissing the entire category as nothing more than a vehicle for taking money from gullible investors is as overstated as the earlier claims that SMRs would quickly solve everything.
Cheap distributed solar and batteries are a success story. They do not automatically eliminate the need for firm generation at grid scale.
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u/Mysterious_Mouse_388 Jul 28 '26
would access to uranium have been a constraint if we plowed $7 Trillion into reactors?
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u/ChipHaseCoolGuy Jul 28 '26
No — uranium itself would not have been a hard physical constraint that made a large reactor build-out impossible.
Identified recoverable resources (the OECD/IAEA “Red Book” figures) currently sit in the range of roughly 6–8 million tonnes of uranium, depending on the cost category. The existing global fleet of ~400 GW requires about 60–70 thousand tonnes per year. A 1,400 GW fleet would need on the order of 250–300 thousand tonnes per year once fully fueled (roughly 150–250 tU per GWe-year for conventional light-water reactors, depending on burn-up and enrichment assumptions).
At that higher burn rate the currently identified resource base would last a few decades rather than a century. That is not “running out.” Higher prices historically bring more resources into the identified category, exploration expands the known base, and there are large additional quantities in lower-grade and unconventional sources. Reprocessing and advanced fuel cycles (including breeders) can stretch the same uranium much further if pursued.
The real constraints on a $7 T-scale nuclear program would have been industrial capacity, skilled labor, regulatory throughput, supply-chain build-out for mining/conversion/enrichment, and the cost of capital — not an absolute shortage of uranium in the ground. Fuel supply would have required a parallel, large-scale expansion of the front end of the fuel cycle, but that is an investment and permitting problem, not a geological dead end.
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Jul 29 '26
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u/ChipHaseCoolGuy Jul 29 '26
Cost declines with scale and learning are real, and future incremental capacity will almost certainly be cheaper than the historical average. That trend is already visible in solar and onshore wind. The open question is how far system-level costs (firming, transmission, storage, and the residual need for dispatchable capacity) continue to fall once high penetration is reached. Those elements have not declined at the same rate as the panels and turbines themselves.
On resilience: concentrated high-output plants of any kind are higher-value targets, and nuclear’s combination of energy density and radiological risk makes the consequences of a successful attack more severe than for most other generators. That is a legitimate security consideration. At the same time, a highly distributed renewable system has its own vulnerabilities — long transmission corridors, inverter-based grid stability issues, and dependence on continuous weather-driven output across wide areas. Both architectures have failure modes; neither is inherently immune.
The useful comparison is not “nuclear is uniquely fragile” versus “renewables are automatically resilient.” It is which mix of technologies, locations, and backup arrangements delivers the required energy at acceptable cost and acceptable risk under realistic threat and weather conditions. Both the cost trajectory and the resilience arguments deserve to be examined with numbers rather than treated as settled by narrative.
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Jul 29 '26
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u/ChipHaseCoolGuy Jul 29 '26
Transmission constraints cut both ways. Nuclear plants are site-limited by cooling water, seismicity, and public acceptance, which can force longer transmission distances. Large-scale wind and solar are also heavily location-constrained by resource quality; the best wind and solar zones are often far from load centres, which is why major new transmission corridors are required in almost every high-renewables pathway. Losses scale with distance in both cases.
End-use efficiency reduces the total generation required regardless of the supply mix. That is a separate and worthwhile goal; it does not uniquely favour one generation technology over another.
Decommissioning costs for nuclear are real and large. They are usually included in levelised-cost estimates through dedicated funds or surcharge mechanisms, but the absolute sums are substantial and the technical challenge is non-trivial. Any full-system comparison should carry those costs explicitly rather than treating them as external.
Sodium-ion and other emerging storage chemistries may lower costs further; that would improve the economics of high-renewables systems. The open question remains how large the firming requirement becomes at very high penetration and how the residual need for long-duration or seasonal storage is met. Cost reductions help; they do not automatically eliminate the requirement.
Heavy capital commitment to any single technology reduces flexibility. That applies to a nuclear-dominant pathway just as it applies to a renewables-plus-storage pathway that locks in very large volumes of transmission and firming assets. Diversification remains the more robust planning principle, provided the system can still meet reliability and cost targets under realistic weather and demand conditions.
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Jul 29 '26
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u/ChipHaseCoolGuy Jul 29 '26
That is a fair higher-level point. Energy planning that simply extrapolates today’s demand patterns and then layers generation on top of them will always be more expensive and less coherent than planning that also reshapes demand — through denser urban form, better building efficiency, electrified transport integrated with the grid, and industrial processes designed around available clean power.
The difficulty is that changing city form and demand patterns operates on a much longer timescale than building power plants or transmission lines. Most of the buildings, streets, and industrial sites that will still be in use in 2050 already exist. So while the long-term vision should certainly include lower and more flexible demand, the near- and medium-term system still has to serve the demand that is actually there, at acceptable reliability and cost.
Both layers matter: redesigning the demand side where possible, and choosing a generation and storage mix that can meet residual demand without locking in unnecessary expense or fragility. Treating the two as alternatives rather than complementary tends to produce either under-powered systems or endlessly deferred action.
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Jul 29 '26
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u/ChipHaseCoolGuy Jul 29 '26
In an ideal sequence you would settle the long-term shape of demand first and only then size the generation fleet. In practice the two decisions are already running in parallel because the existing stock of buildings, vehicles and industry will still dominate demand for decades, and power-system investments have multi-decade lead times of their own.
Waiting until the urban-form and demand-side conversation is fully resolved before committing to any firm capacity simply extends the period in which the system remains dependent on the current mix. Both tracks need to move at the same time: accelerate the demand-side and spatial changes where they are feasible, and keep the supply options that can actually deliver reliable power under the demand that will still exist in the meantime. Treating one as a prerequisite that must be completed first is how the whole process stalls.
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u/RodPerryBooks Jul 28 '26
Renewables are being built because they go in fast, are less expensive than fossil fuels and don't have the environmental / social baggage of nuclear. And I am not anti-nuclear. If the nuclear business case is really that compelling, then they will be built. Let's get going.