The report provides a description of Russia's attacks on the Ukrainian power system, focusing on the winter of 2022-2023. It outlines some of the most important consequences of these attacks and measures taken by Ukraine to manage them. It also provides a basic description of the power system in Ukraine. All information in this report comes from open sources, primarily from public actors in Ukraine, reports, and news media coverage. Starting in October 2022, Russia launched a targeted campaign against the Ukrainian power system in the form of large-scale attacks using thousands of missiles and drones. A large part of the power system was damaged or destroyed, leading to multiple and prolonged power outages. Ukraine has repeatedly managed to repair damaged infrastructure and mitigate the consequences of the power outages, thus avoiding a collapse of the power system. This, in turn, has contributed to enabling continued resistance against Russia's invasion. Prior to the full-scale war, the Ukrainian power system had particular characteristics, such as overcapacity in production and transmission, and a decentralised power system. These conditions, along with a number of measures detailed in this report, have strengthened Ukraine's ability to secure electricity supply during armed attacks.