Solar-electric buses for a university campus transport system

This study explores the prospect of replacing conventional university campus buses powered by fossil fuels with electric ones using primarily solar energy stored in batteries and secondarily the central electricity grid. On the basis of existing infrastructure and facilities in the NTUA campus in Athens (Greece), three scenarios are developed for the collection and use of solar energy for electric buses: (a) bus stop shelters covered with solar panels, (b) installation of solar panels in unused open spaces, and (c) solar roads, i.e. specially engineered panels that can be installed on the road surface. Since the availability of solar energy is linked to sunshine levels, we employ GIS mapping technology to select the locations with the highest solar radiation. For each of the three scenarios, we investigate the optimal technical configuration, the resulting energy generation and the capital cost. The preliminary feasibility analysis shows that scenario (b) presents the lower capital costs in relation to energy generation. Therefore, we further explore this scenario by simulating its daily operation using historical solar radiation data including the actions of buying and selling energy to the central grid, when there is energy deficit or surplus, respectively. Overall, results indicate that, regardless of the high capital costs, solar-powered transportation schemes present a viable alternative for replacing conventional buses at the studied location, yet heavily depend on the choice of Photovoltaic (PV) materials, since capacity factors differ among technologies.