Nuclear plants use fission to split atomic nuclei and release the energy that binds protons and neutrons together. It is the most complex process ever invented to boil water, which powers steam turbines that generate electricity. Greenhouse gas emissions are calculated to be ten to a hundred times higher for coal-fired plants than for nuclear.
Currently, 29 countries have operative nuclear plants; they produce about 11 percent of the world’s electricity. Nuclear is expensive, and the highly regulated industry is often over-budget and slow. While the cost of virtually every other form of energy has gone down over time, nuclear is four to eight times higher than it was four decades ago.
With nuclear power, there is a climate dilemma: Is an increase in the number of nuclear power plants, with all their flaws and inherent risks, worth the gamble? Or, as some proponents insist, will there be a total meltdown of climate by limiting their use?
At Project Drawdown, we consider nuclear a regrets solution. It has potential to avoid emissions, but there are many reasons for concern: deadly meltdowns, tritium releases, abandoned uranium mines, mine-tailings pollution, radioactive waste, illicit plutonium trafficking, and thefts of missile material, among them.
Greenhouse gases…coal [vs.] nuclear: Schlömer S., T., Bruckner, L. Fulton, E. Hertwich, A. McKinnon, D. Perczyk, J. Roy, R. Schaeffer, R. Sims, P. Smith, and R. Wiser. “Technology-Specific Cost and Performance Parameters.” In Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK, and New York: Cambridge University Press, 2014; Warner, Ethan S., and Garvin A. Heath. “Life Cycle Greenhouse Gas Emissions of Nuclear Electricity Generation.” Journal of Industrial Ecology 16, no. S1 (2012): S73-S92.
percent of…electricity and…energy supply: IEA. Key World Energy Statistics. Paris: International Energy Agency, 2016.
operating nuclear reactors: IAEA-PRIS. “Operational & Long-Term Shutdown Reactors.” https://www.iaea.org/PRIS/WorldStatistics/OperationalReactorsByCountry.aspx.
reactors…under construction: IAEA-PRIS. “Under Construction Reactors.” https://www.iaea.org/PRIS/WorldStatistics/UnderConstructionReactorsByCountry.aspx.
France…[percent of] supply: IAEA-PRIS. “Country Statistics: France.” https://www.iaea.org/PRIS/CountryStatistics/CountryDetails.aspx?current=FR.
Generation 3 reactors…in operation: IEA and OECD-NEA. Technology Roadmap: Nuclear Energy. Paris and Issy-les-Moulineaux: International Energy Agency and OECD Nuclear Energy Agency, 2015.
[cost of] advanced nuclear: EIA. Levelized Cost and Levelized Avoided Cost of New Generation Resources in the Annual Energy Outlook 2016. Washington, D.C.: U.S. Energy Information Administration, 2016.; Lazard. Levelized Cost of Energy Analysis 9.0. New York: Lazard. 2015.
coal-fired plants…[in] Asia: Goldenberg, Suzanne. “Plans for Coal-Fired Power in Asia Are ‘Disaster for Planet’ Warns World Bank.” The Guardian. May 5, 2016; Shearer, Christine, Nicole Ghio, Lauri Myllyvirta, Aiqun Yu, and Ted Nace. Boom and Bust 2016: Tracking the Global Coal Plant Pipeline. CoalSwarm, Greenpeace, and Sierra Club, 2016.
China…plants operative and…under construction: IAEA-PRIS. “Country Statistics: China.” https://www.iaea.org/PRIS/CountryStatistics/CountryDetails.aspx?current=CN.
peak carbon dioxide in 2030: Tollefson, Jeff. “China’s Carbon Emissions Could Peak Sooner Than Forecast.” Nature 531, no. 7595 (2016): 425-426.
Amory Lovins [on nuclear]: Lovins, Amory B. Soft Energy Paths for the 21st Century. Boulder: Rocky Mountain Institute, 2011.
James Hansen [on nuclear]: “Top Climate Change Scientists’ Letter to Policy Influencers.” CNN. November 3, 2013.
115 reactors per year: Hansen, James, Kerry Emanuel, Ken Caldeira, and Tom Wigley. “Nuclear Power Paves the Only Viable Path Forward on Climate Change.” The Guardian. December 3, 2015.
Joseph Romm [on nuclear]: Romm, Joe. “Why James Hansen Is Wrong About Nuclear Power.” ThinkProgress. January 7, 2016.
IEA’s estimation…[growth] by 2050: IEA and OECD-NEA, Nuclear Energy.
Olkiluoto reactor in Finland: Stothard, Michael. “Tale of Woe in French Nuclear Sector.” Financial Times. October 13, 2015.
Normandy…pressurized-water reactor: Stothard, “Tale.”
Generation 4 reactors: Eaves, Elisabeth. “Can North America’s Advanced Nuclear Reactor Companies Help Save the Planet?” Bulletin of the Atomic Scientists 73, no. 1 (2017): 27-37; Locatelli, Giorgio, Mauro Mancini, and Nicola Todeschini. “Generation IV Nuclear Reactors: Current Status and Future Prospects.” Energy Policy 61 (2013): 1503-1520.
Correction: Romm summarizes the perspective of the International Energy Agency (IEA): nuclear can play “an important but limited role.”
Correction: China [...] is committing to a combined wind and solar capacity of 320 gigawatts by 2020.
Project Drawdown defines nuclear as: the electricity generation from nuclear fission in the form of Uranium 235 as used in pressurized water reactors, a type of light-water reactor using low-enriched uranium fuel. This solution replaces conventional electricity-generating technologies such as coal, oil, and natural gas power plants.
Commercialized civil nuclear energy captures the energy released by the splitting of atoms in radioactive elements. This energy can be extremely powerful and resource-efficient: 1 kilogram of uranium-235 contains two to three million times the energy equivalent of 1 kilogram of oil or coal (ENS, 2016). During nuclear fission in the reactor core, heat is produced; this heat is used to boil water into steam; the steam then turns turbine blades that drive generators to make electricity.
This analysis models the adoption of nuclear fission as used in pressurized water reactors, a type of light-water reactor using low-enriched uranium fuel, the most prevalent form of nuclear energy in 2016. Advanced reactors such as thorium-based reactors, gas-cooled reactors, pebble bed reactors, and other technologies in the pre-commercialization phases are out of the scope of this research.
Total Addressable Market 
The total addressable market for nuclear electricity generation is based on projected global electricity generation in terawatt-hours from 2020-2050, with current adoption  estimated at around 10.7% of generation (i.e. 2,417 terawatt-hours).
Adoption Scenarios 
Impacts of increased adoption of nuclear from 2020-2050 were generated based on three growth scenarios, which were assessed in comparison to a Reference Scenario where the solution’s market share was fixed at the current levels.
- Plausible Scenario: Based on the evaluation of ambitious scenarios from four global energy systems models,  this scenario follows a high growth trajectory of the adoption cases, capturing 12 percent of the electricity generation market share in 2050 (i.e. 6,239 terawatt-hours).
- Drawdown Scenario: It is assumed that because of the higher adoption of other renewable energy systems, such as wind and solar, the need for new nuclear energy facilities will decline. This scenario is built upon the same trajectories as the Plausible Scenario, but presents a medium growth trajectory, dipping below the Reference Scenario in 2041, and capturing 9.9 percent of the electricity generation market share in 2050.
- Optimum Scenario: With the target of 100 percent electricity generation from no-regrets, renewable energy sources in 2050, this scenario shows the peak in nuclear energy by 2023 followed by a decline to zero in 2050.
The financial inputs used in the model assume an average installation cost of US$4,680 per kilowatt,  in order to capture the rapid cost decrease seen in the last few years. A learning rate of 3% reduces the cost to US$4,575 per kilowatt in 2030 and to US$4,526 per kilowatt in 2050, compared to US$1,923 per kilowatt for the conventional technologies as coal, natural gas, and oil power plants the solution is replacing. An average capacity factor of 82% is used for the solution, compared to 55% for conventional technologies. An average fixed operation and maintenance cost of US$46.87 per kilowatt, and US$0.02 per kilowatt-hour for variable operation and maintenance, are considered for this solution, compared to the US$33.0 per kilowatt and US$0.0037 per kilowatt-hour for the conventional technologies, respectively. A maximum reported cost for Uranium of $0.87 US2010$ per gigajoule was considered (IPCC, 2014).
Through the process of integrating nuclear with other solutions, the total addressable market for electricity generation technologies was adjusted to account for reduced demand resulting from the growth of more energy-efficient technologies,  as well as increased electrification from other solutions like electric vehicles and high-speed rail. Grid emissions factors were calculated based on the annual mix of different electricity generating technologies over time. Emissions factors for each technology were determined through a meta-analysis of multiple sources, accounting for direct and indirect emissions.
Compared to the Reference Scenario, the financial results for the Plausible Scenario of adoption show that the net first costs of US$0.88 billion from 2020-50, and over US$1.7 trillion in savings over the same period. Under the Plausible Scenario, the adoption of nuclear for electricity generation could avoid 16.09 gigatons of carbon dioxide-equivalent greenhouse gas emissions from 2020-2050, compared to a Reference Scenario where the solution is not adopted.
The results of the Plausible Scenario for electricity generation from nuclear (6,239 terawatt-hours in 2050), are slightly lower than the 6,761 terawatt-hours projected by the 2°C Scenario of the International Energy Agency (IEA) for the same year (IEA ETP, 2016). IEA projects a 16.3% market share coming from nuclear, compared to the 12% projected in the Plausible Scenario.
Both the Drawdown and Optimum Scenarios are less ambitious in nuclear energy’s role in the future, with emissions reduction impacts over 2020-2050 of 3.3 gigatons and -44 gigatons, respectively, when compared to the Reference Scenario.
The adoption of nuclear power plants depends on a number of factors. Trends that may accelerate its adoption include: the public acceptance of nuclear power as a climate change abatement and job creation strategy; the commercialization of technologies that produce less radioactive waste; government support (subsidies, loan guarantees, etc.) of nuclear power; and a carbon tax. Trends that may decelerate the adoption of nuclear power plants include: public disapproval of nuclear power, nuclear incidents and accidents, lack of nuclear power skills training, and cost overruns and delays on the construction.
Advantages of increasing nuclear energy adoption include: the zero-carbon nature of generation, provision of baseload capability, a high capacity factor, and the ability to use nuclear’s waste heat to power other systems. The disadvantages of increasing nuclear energy adoption include legacy waste and the public perception of risk that leads to a high cost of capital for new builds.
 For more about the Total Addressable Market for the Energy Sector, click the Sector Summary: Energy link below.
 Current adoption is defined as the amount of functional demand supplied by the solution in the base year of study. This study uses 2014 as the base year due to the availability of global adoption data for all Project Drawdown solutions evaluated.
 To learn more about Project Drawdown’s three growth scenarios, click the Scenarios link below. For information on Energy Sector-specific scenarios, click the Sector Summary: Energy link.
 MESSAGE-Macro 450 scenario; GCAM 450 scenario (AMPERE, 2014); IEA ETP 2°C Scenario (2016); and Greenpeace Energy [R]evolution Scenario (2015).
 All the costs presented are in US2014$.
 For more on Project Drawdown’s Energy Sector integration model, click the Sector Summary: Energy link below.
 For example: LED lighting, heat pumps.
Full models and technical reports coming in late 2017.