Decarbonizing Ukraine’s economy requires thorough planning and stringent measures to reduce Ukraine’s emissions. Modelling supports this process allowing to quantify the emission and economic impacts of alternative paths towards a carbon-neutral Ukraine. The Low Carbon Ukraine (LCU) Project implemented the well-established modelling framework “Long-range Energy Alternatives Planning system” for Ukraine (ULEAP). ULEAP models Ukraine’s greenhouse gas emissions based on a detailed representation of Ukraine’s energy system. In the first part, this documentation describes ULEAP’s modelling approach and its underlying assumptions. The second part is dedicated to the baseline scenario describing emission paths up to the year 2050.