Multi-criteria techno-economic evaluation of electric buses with vehicle-integrated photovoltaic for enhanced sustainability

This study presents a multi-criteria techno-economic evaluation of electric buses (e-buses) equipped with vehicle-integrated photovoltaics (VIPV) to support the global transition toward zero-emission transportation. Aligned with international climate goals like the Paris Agreement and the European Union's 2050 carbon neutrality target, the research assesses ten 12-meter and 18-meter commercial e-bus models from various manufacturers. A computationally efficient methodology is employed, utilizing PVGIS-derived global horizontal irradiation (GHI) data specifically for Gümüşhane, Türkiye. The evaluation framework simultaneously analyzes several critical indicators: PV-based range extension, CO2 emission reduction, grid-connected charging frequency, battery depth of discharge (DoD), and payback period (PP). Findings from the baseline scenario—assuming 50% usable roof area and 22% module efficiency—reveal that e-buses can achieve a daily PV range of up to 19.16 km and annual CO2 emission savings ranging from 1709 to 2596 kg. Additionally, VIPV integration effectively mitigates battery aging by providing a peak DoD reduction of 6.91% and decreases grid-charging dependency by up to 5% during high-irradiance months. In an optimistic scenario featuring 80% usable roof area and 30.1% efficiency, the daily PV range reaches a maximum of 46 km, while the reduction in grid-charging frequency improves significantly to 21.16%. Economic assessments, including Net Present Value (NPV) analysis, confirm the investment's viability, with PPs as short as 3.76 years. This research provides a comprehensive, scalable framework and practical guidance for municipalities and fleet operators to enhance the sustainability of public transport (PT) through solar energy integration.