Annex — methodological notes

Projection scenarios

Wherever possible in this study, values obtained from historic time-series are combined with those obtained from available scenarios or projections, relying on modelling exercises. It is not always possible to represent past and future data consistently due to differences in accounting methodologies and dataset granularity. As an example, passenger activity for domestic navigation in the passenger transport activity section is reported as domestic and international intra-EU maritime in the historic time-series and as domestic navigation in the projection scenario. For this reason, we have reported historic and future scenario data in two separate figures. This study relies on the scenarios described briefly below. Projections shown in this study illustrate expected trends. Many factors will influence actual developments, including the international context, prices and policies.

Fit for 55 scenario (FF55-MIX)

There are three Fit for 55 policy scenarios that serve as a common tool to analyse the impacts of European Green Deal initiatives. In this study, we rely on the MIX scenario. While this cannot fully represent the most recent policies approved or announced at EU or national level, we consider it closest to the current context. The scenario is described as follows:

MIX: relying on both carbon price signal extension to road transport and buildings and strong intensification of energy and transport policies. With its uniform carbon price, it reflects either an extended and fully integrated EU ETS or an existing EU ETS and a new ETS established for road transport and buildings with emission caps set in line with cost-effective contributions of the respective sectors. Maritime transport sector is assumed to be included in the existing EU ETS in MIX.

The MIX scenario is coherent with reducing GHG emissions by at least 55% by 2030 compared to 1990 levels. It also aligns with the EU’s long-term objective of climate neutrality by 2050, aiming for net-zero GHG emissions through the widespread deployment of clean technologies and energy efficiency measures. 

Trends and projections in Europe 2024

In addition to the MIX scenario, which offers projections up to 2030, the study uses the more recent CETO 2024 scenario that includes 2030 and 2050 EU-level projections. CETO 2024 emphasises technology penetration, electrification rates, clean fuels deployment and energy efficiency gains. It includes climate and energy policies adopted up to 2024, including the Fit for 55 package, the EU ETS for road transport and aviation, updated emissions standards, renewable energy shares in transport fuels, and critical policies supporting uptake of hydrogen and clean fuels. It considers phased bans on fossil fuel vehicle sales and deployment mandates for charging infrastructure.

For the CETO 2024 scenario, passenger activity does not cover navigation-related modes of transport. It distinguishes between ‘international intra-EEAwUK’ aviation, which includes flights within the European Economic Area countries plus the UK, and ‘international extra-EEAwUK’, referring to flights departing from or arriving outside the EEA and the UK. For waterborne freight transport, it considers ‘coastal shipping inland waterways’, distinguishing between ‘domestic coastal shipping’ and ‘inland waterways’. CETO 2024 also considers total energy, as opposed to final energy consumption (as in the MIX scenario), referring to the sum of final energy consumption and final non-energy consumption (FNEC). FNEC includes fuels used as raw materials and not consumed as fuel or transformed into another fuel.

Throughout this report, the scenario projections are given for a range of values contained in between the MIX and CETO 2024 estimations. For example, an x% to y% change means the x takes the lowest MIX or CETO 2024 value and the y takes the highest MIX or CETO 2024 value for their respective estimation.

With additional measures scenario

The WAM scenario relies on projections reported by Member States in 2025 (based on projections mostly elaborated in 2024), under Article 18 of the Regulation on the Governance of the Energy Union, whereby each Member State developed an integrated national energy and climate plan. The resulting EU dataset is therefore a compilation of 27 different projections, rather than the result of a single modelling exercise.

The WAM scenario includes all policies and measures that were adopted or implemented at the time of reporting, along with those planned to reach the targets of the European Green Deal and its core dimensions: decarbonisation, energy security, energy efficiency, the internal energy market, and research, innovation and competitiveness. The definition of these ‘additional measures’ is, however, rather flexible and the way this is adopted is heterogeneous across Member States.

Harmonisation of data sources

This report combines several different datasets. To provide a coherent picture across the different sections and figures, the labels used in the original datasets have been harmonised. The following tables provide an overview of the original and harmonised labels for each dataset used in this study, along with the essential information regarding their definition. The reader is referred to the documentation of the datasets for the full descriptions and the corresponding accounting methodologies for transport activity, energy consumption, GHG emissions and air pollutant emissions. Due to varied granularity of the datasets as well as different accounting methodologies, it is not possible to have complete consistency across the chapters (e.g. see the metadata for territorialised road freight transport). It is not possible, for example, to provide final energy consumption, GHG and pollutant emissions with the same sector definitions used to report activity. The time-series reported for each figure corresponds to the full extent available in the original data.  

In particular, shares of the transport sector emissions on overall emissions per pollutant are calculated based on all transport sub-sectors (as reported in the air pollution section of this report). Transport emissions therefore include sub-sectors included in national totals and those that are not. Likewise, for consistency, the overall emissions reflected in the text and figures are the national totals for the entire territory (based on fuel sold), including the transport sub-sectors that are not reported in the national totals. Sub-sectors that are not reported in the national totals are: ‘international aviation cruise’, ‘international maritime navigation’, and ‘domestic aviation cruise’.

Table A1. Original and harmonised labels for the data for historical passenger and freight transport data

Table A2. Original and harmonised labels for the data used to report historic final energy consumption per sector and per fuel

Table A3. Original and harmonised labels for the FF55-MIX scenario used to report activity and energy demand

Table A4. Original and harmonised labels for the historical GHG emission inventories sent by countries to the UNFCCC and the EU Greenhouse Gas Monitoring Mechanism (EU Member States)

Table A5. Original and harmonised labels for the GHG emissions projections reported by Member States as required by the Regulation on the Governance of the Energy Union and Climate Action (Regulation (EU) 2018/1999)

Table A6. Original and harmonised labels for air pollutant emission data

Table A7. Projections data reported to the European Monitoring and Evaluation Programme (EMEP)