The transition toward sustainable urban mobility requires not only the electrification of public transport systems but also a critical assessment of the electricity sources that supply these technologies. This study evaluates the environmental performance of trolleybus systems by integrating operational data with the regional electricity generation mix in which they operate. A Wellto-Tank (WTT) approach is applied, assuming zero Tank-to-Wheel (TTW) emissions, to compare trolleybus operations in two distinct urban contexts: São Paulo (Brazil) and Vilnius (Lithuania). The methodology combines average energy consumption per kilometer with regional electricity carbon intensity data to estimate indirect greenhouse gas (GHG) emissions associated with vehicle operation. The results indicate that the environmental performance of trolleybus systems varies significantly according to the carbon intensity of the electricity supply. In São Paulo, where renewable and low-carbon sources dominate the electricity matrix, trolleybus operations result in substantially lower emissions per kilometer. In contrast, higher electricity carbon intensity in Vilnius leads to increased indirect emissions, despite the use of equivalent zero-emission vehicles. These findings demonstrate that electrified public transport does not automatically guarantee low overall emissions and highlight the importance of aligning transport electrification policies with broader energy transition strategies. By linking fleet operation data with regional electricity matrices, this study provides a replicable framework for assessing the real environmental performance of electric public transport systems.
Rodrigues et al. (Thu,) studied this question.