Electricity is an integral part of all modern economies, supporting a range of critical services. Secure supply of electricity is of paramount importance. The power sector is going through fundamental changes with increasing pressure from climate change. Climate change directly affects every segment of the electricity system altering generation potential and efficiency, testing physical resilience of transmission and distribution networks, and changing demand patterns. Effective policy measures and co-ordinated action among key actors play a central role in building resilience to climate change. This report provides an overview of the climate impacts on electricity systems. It describes how climate change affects each segment of the electricity value chain – generation, transmission and distribution, and demand – with case studies around the world. It proposes a step-by-step application of measures for policy makers and key stakeholders to build the climate resilience of electricity systems.