This publication provides an update on the current status of nuclear power and prospects for its contribution, together with other low carbon energy sources, to ambitious mitigation strategies that will help the world limit global warming to 1.5 C in line with the 2016 Paris Agreement. Since 2000, the IAEA has issued such information and analysis regularly, in order to support those Member States that choose to include nuclear power in their energy system as well as those considering other strategies. The focus of the 2020 publication is on the significant potential of nuclear energy, integrated in a low carbon energy system, to contribute to the 1.5 C climate change mitigation target, and the challenges of realizing this potential. Energy system and market related factors affecting the transition to a low carbon energy system are reviewed. This edition also outlines developments needed to realize the large scale capacity increase required to rapidly decarbonize the global energy system in line with limiting global warming to 1.5 C.