The purpose of this publication is to present the "EU Reference Scenario 2020" (named thereafter "Reference Scenario"), which updates the previous version published in 2016. The Reference Scenario projects the impact of macro-economic, fuel price and technology trends and policies on the evolution of the EU energy system, on transport, and on their greenhouse gas (GHG) emissions. The projections concern the 27 EU Member States individually and altogether. The Reference Scenario also includes GHG emission trends not related to energy. This publication presents and discusses the projection results and analyses various interactions among energy system sectors and impact of different policies. In essence, the Reference Scenario is an informed, internally consistent, and policy relevant projection on the future developments of the EU energy system, transport system and greenhouse gas GHG emissions that acts as a benchmark for new policy initiatives. It reflects policies and market trends used by policymakers as baseline for the design of policies that can bridge the gap between where EU energy and climate policy stands today and where it aims to be in the medium- and long-term, notably in 2030 and 2050.