The Nuclear Debate

  • The underlying question is how electricity is best produced now and in the years to come.
  • Between 1990 and 2019 electricity demand doubled. It is expected to roughly double again by 2050.
  • The Intergovernmental Panel on Climate Change has stated that at least 80% of the world's electricity must be low carbon by 2050 to keep warming within 2 °C of pre-industrial levels.
  • At present, about two-thirds of electricity is produced from the burning of fossil fuels. 
  • Nuclear is proven, scalable and reliable, and its expanded use will be essential for many countries to achieve their decarbonization goals.

Key topics

Topic Key points
Climate change

The electricity & heat sector is the largest source of human-made CO2 emissions. It is also the sector that can most readily be decarbonized.

At least 80% of the world's electricity must be low carbon by 2050 to have a realistic chance of keeping warming within 2 °C of pre-industrial levels according to the latest (5th) Intergovernmental Panel on Climate Change (IPCC) Synthesis Report1.

In 2019, 63% of the world's electricity was generated from the burning of fossil fuels, the same proportion as in 1999, 20 years earlier2. Over the same period, absolute production of electricity from fossil fuels increased by 80%.

The scale of the challenge requires growth of all available clean energy technologies. Whole lifecycle CO2 emissions associated with nuclear energy are among the lowest of all forms of electricity generation, similar to onshore wind3.

Nuclear energy is proven, available today and can be expanded quickly – making it an indispensable part of the solution to climate change.


A supportive energy policy environment that promotes investment in long-term, capital-intensive projects is essential for new nuclear build. Almost all nuclear reactors operating today were built in state-controlled or regulated markets.

Similar to many forms of renewable energy, the majority of costs are upfront capital. Nuclear power plants can operate for decades – in the USA, reactors have been licensed to operate for 80 years – during which time operational costs are generally very low. Over the lifetime of a project, nuclear energy is among the most cost-competitive forms of low-carbon electricity generation4.


Major studies all conclude that nuclear is an exceptionally safe way to produce electricity on an industrial scale. Nuclear has by far the lowest number of direct fatalities of any major energy source per kWh of energy produced – over 100 times less than hydro and liquefied natural gas5.

Serious nuclear accidents are very rare, and not particularly dangerous. The April 1986 Chernobyl accident in Ukraine is the only nuclear accident that has ever led to measurable health effects: 30 fatalities and up to 4000 thyroid cancer cases in those who were children when exposed6, 7, 8. The March 2011 accident at the Fukushima plant in Japan did not cause any immediate health effects, and is unlikely to cause any future health effects according to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)9


All forms of electricity generation produce some form of waste. Nuclear power is the only energy-producing industry that takes full responsibility for managing all its waste. 

Civil nuclear waste has been managed without a significant environmental release for six decades. Unlike some other toxic wastes, such as heavy metals, the principal hazard associated with nuclear waste – its radioactivity – diminishes with time.

Nuclear waste is categorized as low, intermediate or high, according to its level of radioactivity. There are final disposal facilities in operation for low- and intermediate-level waste.

Most high-level waste is used reactor fuel. The amount of reactor fuel requiring disposal is relatively small; the total amount produced by the US nuclear industry over the last 40 years would, if stacked side by side, cover a football field to a height of about seven metres.

The international scientific consensus is for high-level waste to be disposed of in deep geological repositories. The first such repository is due to open in Finland in the 2020s.


Safeguards are effective, and the nuclear power industry does not increase the risk of nuclear weapons proliferation.

North Korea has developed nuclear weapons but has never had nuclear electricity. Over 30 countries have power reactors but only eight are known to have nuclear weapons. Weapons programmes were developed first in most of those countries.

While certain facilities (enrichment and reprocessing) can be used in the production of weapons, the United Nations International Atomic Energy Agency safeguards are effective at policing these. 

Nuclear plants can help in eliminating warheads. Under the now-completed 'Megatons to Megawatts' programme that ran from 1999 to 2013, material from Russian and US stockpiles equivalent to 20,000 bombs was converted to nuclear fuel amounting to 13-19% of global uranium requirements.

Environmental Impact

Nuclear plants have a small environmental footprint and keep the air clean. They require only a small amount of fuel compared to gas or coal, and take up a fraction of the space required for wind and solar farms.

The UK government estimates that Hinkley point C will generate approximately 7% of the UK's electricity10 (currently 24.5 TWh/yr) for 60 years, from a site area of less than 2km2. By contrast, the country's 175-turbine London Array offshore wind farm, the world's largest, generates about 2.5 TWh each year11 from a site area of over 100 km2.  Per unit of area, Hinkley Point C will generate approximately 500 times more electricity than the London Array wind farm.

By preventing the emission of pollutants from other sources, nuclear energy has up to now averted about 2 million pollution-related deaths, and by 2050, is likely to prevent a further 7 million12


Radiation is a naturally occuring phenomenon. 'Man-made' radiation is fundamentally no different from natural radiation in its effects on people.

While radiation is dangerous in high doses, there is no evidence of adverse health effects at low doses. Radiation can be used beneficially in technologies that produce energy, aid medical diagnoses, improve industry and agricultural performance, and help us learn more about our universe.

Nuclear power plants release extremely low levels of radiation. The nuclear industry is responsible for less than 0.1% of the radiation that most people are exposed to in their daily lives13. In advanced countries, most of which produce electricity from nuclear energy, medical exposure such as X-rays, diagnostic imaging and cancer treatment, account for 75% of dose to populations6.

Diversity of supply

All forms of low-carbon electricity generation will need to grow significantly if the world is to control anthropogenic greenhouse gas emissions. Renewables, in particular solar and wind, will play an important role, but are not the whole solution. Two key considerations for energy policy makers are energy density and intermittency:

  1. Energy density. Solar and wind are innately diffuse sources of energy. Powering a modern, and increasingly urban society with renewable energy alone would require many hundreds of times more space than doing so by either fossil fuels or nuclear.
  2. Intermittency. Solar and wind are intermittent sources of energy that require backup. Calculating the additional costs of integrating intermittent renewable electricity sources into an energy system is complicated. Integrating low percentages of renewable energy incurs low costs, but the expense increases non-linearly as penetration grows and very significant backup or storage solutions are required.

At present the only potential complement for a system with high renewables penetration that is low carbon, continuous and scalable, is nuclear.

Notes & references


1. Intergovernmental Panel on Climate Change (IPCC), Climate Change 2014: Synthesis Report – Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (2015) [Back]
2. International Energy Agency, Data and Statistics [Back]
3. IPCC, Renewable Energy Sources and Climate Change Mitigation – Summary for Policymakers and Technical Summary, Special Report of the Intergovernmental Panel on Climate Change, Annex II, Table A.II.4 (2011, reprinted 2012) [Back]
4. OECD International Energy Agency and OECD Nuclear Energy Agency, Projected Costs of Generating Electricity, 2015 Edition (September 2015) [Back]
5. OECD Nuclear Energy Agency, Comparing Nuclear Accident Risks with Those from Other Energy Sources, 2010 [Back]
6. UNSCEAR, Sources and Effects of Ionising Radiation, Report to the UN General Assembly, 2008 [Back]
7. World Health Organization, Health Effects of the Chernobyl Accident and Special Health Care Programmes, Report of the UN Chernobyl Forum Expert Group "Health", 2006 [Back]
8. American Cancer Society, Thyroid Cancer Survival Rates, by Type and Stage (revised 9 January 2020) [Back]
9. United Nations, No Immediate Health Risks from Fukishima Nuclear Accident Says UN Export Science Panel, 2013 [Back]
10. UK Government press release, Government confirms Hinkley Point C project following new agreement in principle with EDF (15 September 2016) [Back]
11. Ørsted website, Renewable energy record achieved at London Array (1 August 2016) [Back]
12. Kharechi and Hansen, Prevented Mortality and Greenhouse Gas Emissions from Historical and Projected Nuclear Power, 2013 [Back]
13. UNSCEAR, Sources and Effects of Ionising Radiation, 2010 [Back]

Key topics Notes & references