Thumb — A comparison of prices over time for energy from nuclear fission and from other sources. Over the presented time, thousands of wind turbines and similar were built on assembly lines in mass production resulting in an economy of scale. While nuclear remains bespoke, many first of their kind facilities added in the timeframe indicated and none are in serial production. *Our World in Data* notes that this cost is the global *average*, while the 2 projects that drove nuclear pricing upwards were in the US. The organization recognises that the median cost of the most exported and produced nuclear energy facility in the 2010s the South Korean APR1400, remained "constant", including in export.^[259]
LCOE is a measure of the average net present cost of electricity generation for a generating plant over its lifetime. As a metric, it remains controversial as the lifespan of units are not independent but manufacturer projections, not a demonstrated longevity.

The nuclear power debate concerns the controversy which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes.^[26]^[260]^[27]

Proponents of nuclear energy regard it as a sustainable energy source that reduces carbon emissions and increases energy security by decreasing dependence on other energy sources that are also^[90]^[91]^[92] often dependent on imports.^[261]^[262]^[263] For example, proponents note that annually, nuclear-generated electricity reduces 470 million metric tons of carbon dioxide emissions that would otherwise come from fossil fuels.^[264] Additionally, the amount of comparatively low waste that nuclear energy does create is safely disposed of by the large scale nuclear energy production facilities or it is repurposed/recycled for other energy uses.^[265] M. King Hubbert, who popularized the concept of peak oil, saw oil as a resource that would run out and considered nuclear energy its replacement.^[266] Proponents also claim that the present quantity of nuclear waste is small and can be reduced through the latest technology of newer reactors and that the operational safety record of fission-electricity in terms of deaths is so far "unparalleled".^[15] Kharecha and Hansen estimated that "global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO₂-equivalent (GtCO₂-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning" and, if continued, it could prevent up to 7 million deaths and 240 GtCO₂-eq emissions by 2050.^[205]

Proponents also bring to attention the opportunity cost of using other forms of electricity. For example, the Environmental Protection Agency estimates that coal kills 30,000 people a year,^[267] as a result of its environmental impact, while 60 people died in the Chernobyl disaster.^[268] A real world example of impact provided by proponents is the 650,000 ton increase in carbon emissions in the two months following the closure of the Vermont Yankee nuclear plant.^[269]

Opponents believe that nuclear power poses many threats to people's health and environment^[270]^[271] such as the risk of nuclear weapons proliferation, long-term safe waste management and terrorism in the future.^[272]^[273] They also contend that nuclear power plants are complex systems where many things can and have gone wrong.^[274]^[275] Costs of the Chernobyl disaster amount to ≈$68 billion as of 2019 and are increasing,^[35] the Fukushima disaster is estimated to cost taxpayers ~$187 billion,^[190] and radioactive waste management is estimated to cost the Eureopean Union nuclear operators ~$250 billion by 2050.^[192] However, in countries that already use nuclear energy, when not considering reprocessing, intermediate nuclear waste disposal costs could be relatively fixed to certain but unknown degrees^[276] "as the main part of these costs stems from the operation of the intermediate storage facility".^[277]

Critics find that one of the largest drawbacks to building new nuclear fission power plants are the large construction and operating costs when compared to alternatives of sustainable energy sources.^[55]^[278]^[84]^[244]^[279] Further costs include ongoing research and development, expensive reprocessing in cases where such is practiced^[73]^[74]^[75]^[77] and decommissioning.^[280]^[281]^[282] Proponents note that focussing on the levelized cost of energy (LCOE), however, ignores the value premium associated with 24/7 dispatchable electricity and the cost of storage and backup systems necessary to integrate variable energy sources into a reliable electrical grid.^[283] "Nuclear thus remains the dispatchable low-carbon technology with the lowest expected costs in 2025. Only large hydro reservoirs can provide a similar contribution at comparable costs but remain highly dependent on the natural endowments of individual countries."^[284]

Overall, many opponents find that nuclear energy cannot meaningfully contribute to climate change mitigation. In general, they find it to be, too dangerous, too expensive, to take too long for deployment, to be an obstacle to achieving a transition towards sustainability and carbon-neutrality,^[84]^[285]^[286]^[287] effectively being a distracting^[288]^[289] competition for resources (i.e. human, financial, time, infrastructure and expertise) for the deployment and development of alternative, sustainable, energy system technologies^[85]^[289]^[84]^[290] (such as for wind, ocean and solar^[84] – including e.g. floating solar – as well as ways to manage their intermittency other than nuclear baseload^[291] generation such as dispatchable generation, renewables-diversification,^[292]^[293] super grids, flexible energy demand and supply regulating smart grids and energy storage^[294]^[295]^[296]^[297]^[298] technologies).^[299]^[300]^[301]^[302]^[303]^[304]^[305]^[306]^[251]

Nevertheless, there is ongoing research and debate over costs of new nuclear, especially in regions where i.a. seasonal energy storage is difficult to provide and which aim to phase out fossil fuels in favor of low carbon power faster than the global average.^[307] Some find that financial transition costs for a 100% renewables-based European energy system that has completely phased out nuclear energy could be more costly by 2050 based on current technologies (i.e. not considering potential advances in e.g. green hydrogen, transmission and flexibility capacities, ways to reduce energy needs, geothermal energy and fusion energy) when the grid only extends across Europe.^[308] Arguments of economics and safety are used by both sides of the debate.

Comparison with renewable energy

Slowing global warming requires a transition to a low-carbon economy, mainly by burning far less fossil fuel. Limiting global warming to 1.5 °C is technically possible if no new fossil fuel power plants are built from 2019.^[309] This has generated considerable interest and dispute in determining the best path forward to rapidly replace fossil-based fuels in the global energy mix,^[310]^[311] with intense academic debate.^[312]^[313] Sometimes the IEA says that countries without nuclear should develop it as well as their renewable power.^[314]

World total primary energy supply of 162,494 TWh (or 13,792 Mtoe) by fuels in 2017 (IEA, 2019)^[315]^: 6, 8

Oil (32%)

Coal/Peat/Shale (27.1%)

Natural Gas (22.2%)

Biofuels and waste (9.5%)

Nuclear (4.9%)

Hydro (2.5%)

Others (Renewables) (1.8%)

Several studies suggest that it might be theoretically possible to cover a majority of world energy generation with new renewable sources. The Intergovernmental Panel on Climate Change (IPCC) has said that if governments were supportive, renewable energy supply could account for close to 80% of the world's energy use by 2050.^[316] While in developed nations the economically feasible geography for new hydropower is lacking, with every geographically suitable area largely already exploited,^[317] some proponents of wind and solar energy claim these resources alone could eliminate the need for nuclear power.^[313]^[318]

Nuclear power is comparable to, and in some cases lower, than many renewable energy sources in terms of lives lost in the past per unit of electricity delivered.^[203]^[201]^[319] Depending on recycling of renewable energy technologies, nuclear reactors may produce a much smaller volume of waste, although much more toxic, expensive to manage and longer-lived.^[320]^[247] A nuclear plant also needs to be disassembled and removed and much of the disassembled nuclear plant needs to be stored as low-level nuclear waste for a few decades.^[321] The disposal and management of the wide variety^[322] of radioactive waste, of which there are over one quarter of a million tons as of 2018, can cause future damage and costs across the world for over or during hundreds of thousands of years^[323]^[324]^[325] – possibly over a million years,^[326]^[327]^[328]^[329] due to issues such as leakage,^[330] malign retrieval, vulnerability to attacks (including of reprocessing^[76]^[73] and power plants), groundwater contamination, radiation and leakage to above ground, brine leakage or bacterial corrosion.^[331]^[326]^[332]^[333] The European Commission Joint Research Centre found that as of 2021 the necessary technologies for geological disposal of nuclear waste are now available and can be deployed.^[334] Corrosion experts noted in 2020 that putting the problem of storage off any longer "isn't good for anyone".^[335] Separated plutonium and enriched uranium could be used for nuclear weapons, which – even with the current centralized control (e.g. state-level) and level of prevalence – are considered to be a difficult and substantial global risk for substantial future impacts on human health, lives, civilization and the environment.^[73]^[246]^[247]^[248]^[249]

Speed of transition and investment needed

Analysis in 2015 by professor Barry W. Brook and colleagues found that nuclear energy could displace or remove fossil fuels from the electric grid completely within 10 years. This finding was based on the historically modest and proven rate at which nuclear energy was added in France and Sweden during their building programs in the 1980s.^[336]^[337] In a similar analysis, Brook had earlier determined that 50% of all global energy, including transportation synthetic fuels etc., could be generated within approximately 30 years if the global nuclear fission build rate was identical to historical proven installation rates calculated in GW per year per unit of global GDP (GW/year/$).^[338] This is in contrast to the conceptual studies for 100% renewable energy systems, which would require an order of magnitude more costly global investment per year, which has no historical precedent.^[339] These renewable scenarios would also need far greater land devoted to onshore wind and onshore solar projects.^[338]^[339] Brook notes that the "principal limitations on nuclear fission are not technical, economic or fuel-related, but are instead linked to complex issues of societal acceptance, fiscal and political inertia, and inadequate critical evaluation of the real-world constraints facing [the other] low-carbon alternatives."^[338]

Scientific data indicates that – assuming 2021 emissions levels – humanity only has a carbon budget equivalent to 11 years of emissions left for limiting warming to 1.5 °C^[340]^[341] while the construction of new nuclear reactors took a median of 7.2–10.9 years in 2018–2020,^[333] substantially longer than, alongside other measures, scaling up the deployment of wind and solar – especially for novel reactor types – as well as being more risky, often delayed and more dependent on state-support.^[342]^[343]^[286]^[288]^[84]^[344]^[299] Researchers have cautioned that novel nuclear technologies – which have been in development since decades,^[345]^[84]^[278] are less tested, have higher proliferation risks, have more new safety problems, are often far from commercialization and are more expensive^[278]^[84]^[244]^[346] – are not available in time.^[80]^[85]^[347]^[288]^[348]^[298]^[349] Critics of nuclear energy often only oppose nuclear fission energy but not nuclear fusion; however, fusion energy is unlikely to be commercially widespread before 2050.^[350]^[351]^[352]^[353]^[354]

Land use

The median land area used by US nuclear power stations per 1 GW installed capacity is 1.3 square miles (3.4 km²).^[355]^[356] To generate the same amount of electricity annually (taking into account capacity factors) from solar PV would require about 60 square miles (160 km²), and from a wind farm about 310 square miles (800 km²).^[355]^[356] Not included in this, is land required for the associated transmission lines, water supply, rail lines, mining and processing of nuclear fuel, and for waste disposal.^[357]