Comparative Analysis of the Relationship Between Electric Bus Adoption and Electricity Grid Emission Intensity in European Countries

Transport is responsible for a considerable part of greenhouse gas emissions in the European Union. Electrification of urban bus fleets is treated as one of the basic instruments of decarbonisation of this sector. The climate benefit obtained from such a transition depends, however, on the emission intensity of the electricity used for charging. The paper assesses the strength and direction of the relationship between the share of electric buses in national fleets and the Grid Emission Intensity indicator (GEI) for 28 European countries in the period 2015–2024. GEI was calculated on the basis of panel data from Ember and Eurostat as a weighted average of CO2eq emissions per kWh of electricity generated in country and year, taking into account the fuel structure of the national energy mix and IPCC emission factors. Descriptive statistics, Pearson correlation and k-means clustering were applied. The number of clusters (k = 4) was established using the elbow method and the silhouette coefficient. A strong negative correlation between the share of electric buses and GEI was obtained at the EU level. In 26 of the 28 analysed countries the relationship was negative. Cluster analysis distinguished four groups of countries differing significantly in the level of fleet electrification and in the emission intensity of the electricity mix.