What is the role of nuclear power in clean energy transitions?

Nuclear power accounts for about 10% of electricity generation globally, rising to almost 20% in advanced economies. It has historically been one of the largest global contributors of carbon-free electricity and while it faces challenges in some countries, it has significant potential to contribute to power sector decarbonisation.

Nuclear power plants contribute to electricity security in multiple ways by keeping power grids stable and complementing decarbonisation strategies since, to a certain extent, they can adjust their output to accompany shifts in demand and supply. As the share of variable renewables like wind and solar photovoltaics (PV) rises, the need for such services will increase.

Nuclear power faces a contrasted future despite its ability to produce emissions-free power. With large up-front costs, long lead times and an often-poor record of on-time delivery, nuclear power projects have trouble in some jurisdictions competing against faster-to-install alternatives, such as natural gas or modern renewables. It also faces public opposition in many countries. Its uncertain future could result in billions of tonnes of additional carbon emissions.

Amid today’s global energy crisis, reducing reliance on imported fossil fuels has become the top energy security priority. No less important is the climate crisis: reaching net zero emissions of greenhouse gases by mid-century requires a rapid and complete decarbonisation of electricity generation and heat production. Nuclear energy, with around 413 gigawatts (GW) of capacity operating in 32 countries, contributes to both goals by avoiding 1.5 gigatonnes (Gt) of global emissions and 180 billion cubic metres (bcm) of global gas demand a year.

While wind and solar PV are expected to lead the push to replace fossil fuels, they need to be complemented by dispatchable resources. As today’s second largest source of low emissions power after hydropower, and with its dispatchability and growth potential, nuclear – in countries where it is accepted – can help ensure secure, diverse low emissions electricity systems.

Nuclear power is an important low-emission source of electricity, providing about 10% of global electricity generation. For those countries where it is accepted, it can complement renewables in reducing power sector emissions while also contributing to electricity security as a dispatchable power source. It is also an option for producing low-emission heat and hydrogen.  

More efforts are needed to get nuclear power on track with the Net Zero Emissions by 2050 Scenario. Lifetime extensions of existing nuclear power plants are one of the most cost-effective sources of low-emission electricity, and there have been several positive policy developments to take full advantage of these opportunities including in the United States, France and Japan. Additional effort is needed to accelerate new constructions – 8 GW of new nuclear capacity was brought online in 2022, but the Net Zero Scenario calls for over four-times as much annual deployment by 2030. Support for innovation in nuclear power, including small modular reactors, will also help expand the range of low-emission options and widen the path to net zero power. 

Many countries have recently taken steps to extend operations at existing nuclear power plants and build new ones

Countries and regions making notable progress to advance nuclear electricity include: 

Belgium recently decided to extend the operation of two existing reactors from 2025 to 2035, which will meet around 15% of electricity demand. 

Canada introduced an investment tax credit of up to 30% for clean energy technologies in late 2022, explicitly including small modular reactors (SMRs), and Canada’s Infrastructure Bank granted a loan to build an SMR as early as 2028 at an existing nuclear site. 

China continues to lead in nuclear capacity additions, with two large reactors completed in 2022, four more starting construction and plans to further accelerate deployment. 

Finland completed Olkiluoto 3 in 2023, the first new nuclear reactor in Western Europe in 15 years. 

France agreed in 2022 to construct 6 new large nuclear reactors that will meet around 10% of electricity demand, with an option to build 8 more. The first reactor is targeting 2035 for commissioning.  

Japan established a law in 2023 under the Green Transformation initiative that allows power companies to operate nuclear assets for longer, in some cases over 60 years, by excluding periods during which they were suspended for safety reasons. A new policy announced in December 2022 also aims to maximise the use of the existing fleet and foresees the development of new nuclear power plants. 

Korea aims for nuclear power to expand to over 30% of electricity generation by 2030 under the 10th Basic Energy Plan, up from 28% currently. 

In Poland, the cabinet formally approved in November 2022 the decision that the first nuclear power plant in Poland will use three Westinghouse AP1000 units. In addition, the development of APR1400 units are progressing, and SMRs continue to gain traction among the private sector. 

The United Kingdom's 2022 Energy Security Strategy targets 8 new large reactors, as well as SMRs, to achieve nuclear power capacity of 24 GW by 2050, which could provide up to 25% of projected electricity demand. 

In the United States, the Inflation Reduction Act of 2022 created a tax credit for the production of zero-emission nuclear power, dramatically improving the economics of existing nuclear reactors with additional support for nuclear new-build also included.