Five Reasons the Clean Energy Transition Needs Nuclear Power

Nuclear energy ranks among the cleanest power sources when assessed across its entire lifecycle. Lifecycle analyses consider every stage — from uranium mining and fuel fabrication to plant construction, operation and decommissioning. Even with all these phases included, nuclear power’s total greenhouse gas emissions remain extremely low, comparable to wind and lower than solar.  

This is because nuclear reactors produce electricity without releasing carbon dioxide during operation, and advances in technology continue to reduce emissions from earlier stages of the fuel cycle. New reactor designs — including small modular reactors— are being developed to provide flexible, dispatchable clean energy and further minimize total emissions.  

According to the IAEA’s Power Reactor Information System (PRIS), as of 20 January 2026, 415 reactors were in operation worldwide, providing 376.0 GW(e) of nuclear capacity and supplying hundreds of millions of homes with low‑carbon electricity.  

Nuclear power plants can provide a continuous and reliable supply of energy because they operate at full capacity nearly uninterrupted. This contrasts with variable renewable energy sources, such as solar and wind, whose output depends on weather conditions and typically requires backup or storage.  

This reliability is critical because: 

•  energy demand continues to grow globally.
• nuclear power complements renewables by supplying constant power, smoothing variability and reducing reliance on fossil fuel backup during lulls in wind or solar power.
• Nuclear power is increasingly being explored as a solution to meet the growing electricity demand for data centres. At the same time, AI offers powerful tools to optimize reactor performance, streamline construction and enhance operational efficiency — enabling nuclear energy to reach its full potential while maintaining standards of safe and security.   

Momentum to increase financing for nuclear energy is growing. The IAEA is expanding its cooperation with a range of international financial institutions  to support countries in exploring and financing nuclear energy, including nuclear power plants (NPPs). These partnerships include engagement with the WBG, the Asian Development Bank, the European Bank for Reconstruction and Development and OPEC Fund. 

A total of 33 countries have endorsed the Declaration to Triple Nuclear Energy, signalling a collective ambition to triple global nuclear energy capacity by 2050.  The signatories span a wide geographic range across continents and include newcomer countries such as El Salvador, Ghana, Jamaica, Kazakhstan and Rwanda. 

At the UN Climate Change Conference (COP28) in Dubai 2023, nuclear energy was included in the  Global Stocktake, which called for its accelerated deployment alongside other low carbon energy sources. 

The second Nuclear Energy Summit will be hosted by the Government of France in Paris on 10 March. It follows the previous Nuclear Energy Summit in 2024, in which world leaders gathered in Brussels to highlight the role of nu

High-temperature reactors, small modular reactors (SMRs) and hybrid systems can generate low-carbon heat for industrial processes, in sectors such as steel, cement, and chemical production.  Maritime transport can be enabled by SMRs or microreactors for port electrification and onboard nuclear propulsion. 

Nuclear technology continues to evolve, to become more fit for purpose for future needs. New reactor designs offer higher safety margins, improved efficiency and longer operating lifetimes, while small modular reactors (SMRs) and other advanced systems provide greater flexibility in how and where nuclear power can be deployed. 

SMRs are designed to shorten construction timelines, have lower upfront capital requirements and provide enhanced load‑following capabilities, allowing them to complement variable renewable energy sources such as wind and solar. 

Advanced reactor concepts are also being developed to improve fuel efficiency, reduce waste volumes and expand the use of alternative fuels.  

Fusion is progressing as a potential long-term clean energy source. The IAEA’s World Fusion Outlook 2025 shows that fusion is now emerging as a strategic national priority for research and development. The second Ministerial Meeting of the IAEA World Fusion Energy Group was held in Chengdu, China to discuss policies and initiatives on fusion—a potentially abundant source of clean energy capable of meeting growing development needs. 

The IAEA supports countries pursuing nuclear power programmes by providing data, analysis and knowledge on how nuclear power can contribute towards decarbonization and climate action. Through its work, the IAEA helps build skills, encourages innovation and strengthens countries’ capacities to plan and manage their energy systems. These efforts help countries meet growing energy needs, improve energy security and reduce environmental impacts, including those related to environmental change.