The growing consumption of fossil fuels and its negative environmental consequences have been a major concern during the last few decades. In line with that, public transport operators face global pressure to replace diesel buses by battery-electric buses (BEBs) in many countries. However, BEBs need to be recharged several times throughout the day to avoid running out of energy due to their limited driving range and slow charging rate. Accordingly, operating BEBs is substantially more sensitive to unanticipated delays and excess energy consumption, which raises serious challenges with respect to charging schedules. Moreover, BEBs are only a truly sustainable alternative if they are powered by renewable energy generators (REGs), which have intermittent and uncertain generation. Thus, we design and propose a real-time decision support system to overcome these uncertainties and maximize the utilization of REGs and minimize the impact on the grid while guaranteeing a feasible operation for the BEBs.