How first comes energy efficiency? Assessing the energy efficiency first principle in the EU using a comprehensive indicator-based approach

Abstract The energy efficiency first (EE1) principle was defined and established as a leading of the European Union’s policy with Clean Energy for All Europeans package in 2016. requires demand resources to be considered on par supply-side solutions prioritized whenever they are less costly or deliver more value than alternative options. This approach should applied every planning process, decision-making, investment regarding sector. In order examine which degree EE1 is actually implemented by Member States, we developed composite indicator, consists 13 criteria. These criteria capture multiple facets thus can also used guide EU States their operationalization principle. After development methodology, indicator-based tested assess implementation national climate plans 14 States. aim this step demonstrate feasibility indicator its applicability an assessment tool across different countries EU. results imply that fundamentals understood realized. Nevertheless, most would still fail ensure equal treatment between supply demand-side neglect benefits associated improvements. However, those finding caution since only limited data test