Net-zero energy synergies of utilising electric shuttle buses to remotely share energy between zero-energy commercial and transportation buildings

Abstract

Hybrid renewable energy sources are crucial for realising global carbon neutrality goal, however, intermittent generation hinders efficient utilisation. Electric vehicles are promising for sharing the surplus renewable energy and benefitting systems. This study investigated a zero-emission system with hybrid solar and wave renewable energy sources comprising electric shuttle buses and two remote buildings of remarkably different magnitudes. Weather, building, bus, renewables, and energy management systems were modelled in TRNSYS 18. Battery operational and renewables design constraints were integrated into the model. The techno-economic-environmental performances were assessed by energy matching indices, relative net present value and annual operational equivalent carbon dioxide emissions. Parametric simulations were conducted to explore the impacts of the sizes of renewable energy systems, parking duration control, bus group control, and building-to-vehicle and vehicle-to-building functions. Optimal solutions were selected based on the weighted sum method. A sensitivity analysis revealed the impacts of facility charging and discharging power limits, utility escalation ratios, interest rates, and feed-in tariffs. Designing lower renewable generation in smaller buildings benefitted the system, with a 60 % hotel renewable energy generation ratio. Parking duration and bus group control enhanced the techno-economic performance of the system. For sensitivity analysis, a 1-C charging and discharging power limit sufficiently supported the energy sharing by electric shuttle buses, and a 0.25HKD/kWh feed-in tariff could help the system's relative net present value reach zero. The results are expected to guide the design of zero-emission systems.