Decarbonization Pathway for Train Systems Using a Supercapacitor Energy Storage Charged by Distributed Solar PV Systems: A Case Study for Saudi Arabia

The study aims to introduce a novel system that powers a passenger train using supercapacitor energy storage that is charged by a solar carport system located at each train stop station. The system’s detailed design and its techno-economic analysis have been carried out and applied to a case study of a supercapacitor-based train (SC-Train) that connects an international airport with five major cities in the eastern region of Saudi Arabia. The objective is to reduce CO2 emissions from Saudi Arabia’s transportation sector utilizing an electric-operated train energized by a solar carport system. The solar carport system is designed to have a capacity equal to the train’s energy consumption. Additionally, the supercapacitor has been selected as a storage device to utilize the regenerative braking system feature to enhance the train’s energy efficiency, which results in energy savings equivalent to 44.9% of total energy consumption. Finally, the project’s feasibility has been determined via the benefit–cost analysis approach, which yields a positive net present value of USD 367 million over 30 years.