Spatially differentiated energy and environment comparison of diesel and electric buses

Urban transport increasingly faces the twin global challenges of oil depletion and climate change. Two additional concerns in most cities are local air and noise pollution. Electric public transport vehicles could potentially help alleviate all four problems. Here we compare the energy, climate, and air and noise pollution implications of diesel and electric vehicle (EV) buses. Full fuel cycle energy and CO₂ emissions per km of route were modelled, with the number of stops per km varied to represent inner and outer urban routes. We find that per km of route, EV buses hold an advantage over diesel buses on full fuel cycle energy use. But given current means of electricity production, minimum CO₂ emissions of both vehicle types are almost identical, although these occur at a slightly lower average speed for diesel than for EV buses. We also find significant air and noise pollution benefits of EV over diesel buses, especially for inner city routes. This advantage is expected, because the higher density of population for the inner route magnifies the health risks of air and noise pollution. Finally, the results are generalised to aid decision-making about the benefits of electric buses in other cities, both in Australia and overseas.