Nuclear reactors worldwide have helped avoid the emission of 72 billion tonnes of carbon dioxide since 1970, compared to coal-fired electricity generation, according to a new report.

Nuclear reactors generated a total of 2,553 terawatt-hour (TWh) in 2020, down from 2,657 TWh in 2019, showed the report released days ahead of the 26th Conference of Parties (CoP26) To the United Nations Framework Convention on Climate Change.

Reduced electricity demand resulting from the novel coronavirus disease (COVID-19) pandemic saw generators curtail output in response, the World Nuclear Performance Report 2021 stated.

In 2020, power generation declined in Africa, North America and in West and Central Europe. Generation rose in Asia, although by a much smaller amount than in recent years. Generation was almost unchanged in East Europe and Russia and South America, the report said.

In 2020, the end of year capacity of operable nuclear power plants was 392 Gigawatt electrical (GWe).

In most years, a small number of operable reactors do not generate electricity. At the end of 2020, there were 441 operable reactors, the report noted.

Sama Bilbao y Leon, director-general of World Nuclear Association that conducted the study, said:

More than half of the reactors permanently shut down in the last few years were not because of technical limitations but because of political phase-out policies or the failure of markets to adequately recognise the value of on-demand, low-carbon, reliable nuclear power. This is a loss of low-carbon generation that the world can ill-afford to squander.

Six reactors were permanently shut down in 2020, according to the authors of the report:

The two Fessenheim reactors were closed as a result of a political decision to reduce the share of nuclear generation in the French electricity generation mix

The two US reactors closed because of market conditions

Ringhals 1 in Sweden went offline from March 2020 for a maintenance outage and remained offline due to low electricity demand. It returned to service in June to provide grid stability.

In Russia, the Leningrad reactor closed as the second of two new reactors at the site started up to replace it.

Five reactors were connected to the grid in 2020. Two countries, Belarus and the United Arab Emirates, were hosting their first nuclear reactors. Both countries have further units under construction.

Nuclear power contributes to tackling climate change, for example, by providing 10 per cent of the world’s electricity, according to International Atomic Energy Agency. This is close to a third of the global low-carbon electricity.

Nuclear electricity generation will need to double between 2020 and 2050 if the world is to meet its net-zero ambitions, the International Energy Agency’s Net-Zero by 2050 Roadmap projected.