Investments$141 to $220 per megawatt-hour. That’s where Lazard puts new-build nuclear generation in the US today, well above new-build natural gas combined cycle at $48 to $109/MWh. Anyone arguing SMRs win on cost alone is skipping half the spreadsheet. But cost is only one column, and the other two, safety and emissions, tell a very different story. Here’s what the actual data says across all three. ⚡
This isn’t a cheerleading exercise for nuclear, and it isn’t a hit piece on gas or coal either. It’s a straight comparison using Lazard’s 2025 LCOE+ report, Our World in Data’s mortality figures, and the IPCC’s lifecycle emissions analysis, the same three sources any serious analyst would reach for. 📊
Cost: the sticker shock and the subsidy math
Nuclear’s cost problem is real, and pretending otherwise does the sector no favors. Lazard’s 2025 LCOE+ report puts new-build nuclear at $141 to $220/MWh unsubsidized, against $48 to $109/MWh for new gas combined cycle and $71 to $173/MWh for new coal. Gas peaking plants are the one fossil category nuclear actually beats on paper, running $149 to $251/MWh. 💰
The gap gets worse before it gets better, because first-of-a-kind SMR economics are brutal. NuScale’s Carbon Free Power Project in Idaho saw its target price jump from $58/MWh to $89/MWh as construction costs rose 75%, from $5.3 billion to $9.3 billion, before the project’s utility customers walked away and NuScale cancelled it in 2023. Wood Mackenzie pegs current FOAK SMR costs around $180/MWh, with nth-of-a-kind production potentially bringing that down to roughly $100/MWh by 2030, a forecast that depends entirely on someone actually building enough reactors to reach that scale.
Two things are pulling nuclear’s real-world economics in the opposite direction from that Lazard chart, though. First, hyperscalers with balance sheets that dwarf any municipal utility are underwriting the FOAK premium directly: Meta’s agreement covering up to 8 TerraPower Natrium reactor plants and Amazon’s $50 billion partnership with X-energy for 960 MW of Xe-100 capacity both remove the financing risk that killed NuScale’s Idaho project. Second, gas isn’t standing still either. Lazard’s own 2025 report flags new combined-cycle gas turbine costs at a 10-year high thanks to turbine shortages and rising equipment costs, which narrows the gap from the other direction. Tracking which side of that gap closes faster, project by project, is exactly the kind of thing SMRbrief Pro members can search, filter, and export the full intelligence picture behind developments like this one.
New-build nuclear (Lazard 2025): $141-220/MWh
New-build gas combined cycle: $48-109/MWh
New-build coal: $71-173/MWh
Gas peaking: $149-251/MWh
FOAK SMR (Wood Mackenzie estimate): ~$180/MWh, trending toward ~$100/MWh NOAK by 2030
Safety: the deaths-per-terawatt-hour gap fossil fuels can’t close
This is where the comparison stops being close. Nuclear power causes roughly 0.03 deaths per terawatt-hour of electricity generated, according to Our World in Data’s analysis, a figure that already includes Chernobyl and Fukushima. Coal causes 24.62 deaths per TWh. Oil causes 18.43. Even natural gas, the cleanest-burning fossil fuel, causes 2.82 deaths per TWh, almost entirely from air pollution rather than accidents. Run the math and nuclear results in 99.8% fewer deaths than coal per unit of electricity produced. 🔬
The regulatory system is starting to reflect that math. In 2023 the NRC finalized a performance-based emergency preparedness rule that lets SMR developers calculate a plant-specific emergency planning zone based on actual accident consequences, instead of defaulting to the 10-mile zone required for conventional reactors, on the argument that passive safety designs cap how much radioactive material could ever escape. The Union of Concerned Scientists opposed the rule, and that disagreement is legitimate: a statistically safe technology can still fail badly in a specific instance, and probability isn’t the same thing as certainty. Fair point. It doesn’t change the underlying mortality data, though, which fossil fuels have never come close to matching even before you count the roughly 1 million to 2.5 million annual deaths attributed globally to fossil-fuel air pollution.
Nuclear: ~0.03 deaths/TWh (includes Chernobyl and Fukushima)
Natural gas: 2.82 deaths/TWh
Oil: 18.43 deaths/TWh
Coal: 24.62 deaths/TWh
Emissions: the lifecycle numbers behind the “clean” label
Cost is nuclear’s weak spot and safety is its strongest argument. Emissions sit close to the strong end too, though not by quite the margin some advocates claim. 🌍 The IPCC’s median lifecycle estimate puts nuclear at roughly 12 grams of CO2-equivalent per kilowatt-hour, comparable to wind and lower than solar, against roughly 490 g/kWh for natural gas combined cycle and 820 g/kWh for coal. That’s a lifecycle number, covering mining, construction, and decommissioning, not just the zero direct emissions at the point of generation. The UN Economic Commission for Europe ran its own 2022 analysis and landed even lower, at 5.1 to 6.4 g/kWh for nuclear, the lowest figure among all low-carbon technologies it assessed.
There’s real spread in the academic literature worth acknowledging rather than glossing over. Some published life-cycle assessments put nuclear’s emissions as high as 100+ g/kWh depending on uranium enrichment method and ore grade, since gaseous diffusion enrichment runs roughly twice the emissions of centrifuge enrichment. That’s not nothing. But even the high end of that range sits an order of magnitude below coal, and centrifuge enrichment, the method Centrus Energy and most Western suppliers now use, sits at the low end.
Capacity factor matters here too, because a plant that runs constantly displaces more fossil generation than one that runs intermittently. US nuclear plants operated above 93% capacity factor in 2023. Natural gas combined-cycle plants averaged closer to 57%, and coal plants ran at just 42.5% in 2024, according to EIA data, meaning both fossil categories need standby backup capacity that nuclear generally doesn’t.
Nuclear lifecycle emissions (IPCC median): ~12 g CO2eq/kWh
Natural gas combined cycle: ~490 g CO2eq/kWh
Coal: ~820 g CO2eq/kWh
Nuclear capacity factor (US, 2023): 93%+
Gas/coal capacity factor: 57% and 42.5%, respectively
Where fossil fuels still win, for now
None of this makes SMRs the obvious choice in every situation, and pretending otherwise would be exactly the kind of breathless optimism this publication tries to avoid. Gas remains cheaper to build, faster to permit, and vastly more flexible for utilities that need to add capacity in 18 months rather than a decade. GE Hitachi’s 300 MWe BWRX-300, now under construction at Darlington, Ontario, and TerraPower’s 345 MWe Natrium plant, which broke ground in Kemmerer, Wyoming this spring, are both multi-year projects competing against gas turbines that can be ordered, built, and running well before either reactor produces its first electron. 🚀
Have you run these numbers against a specific project you’re tracking, and did the comparison land where you expected? The honest read is that nuclear wins decisively on safety, wins comfortably on emissions, and still has real ground to make up on cost, ground that depends less on reactor physics than on whether Meta, Amazon, and Google keep writing the checks that get FOAK projects to NOAK pricing.