Hydrogen-electricity hybrid energy pipelines for railway transportation: Design and economic evaluation

With the decarbonization and electrification of modern railway transportation, the demand for both the highcapacity electrical energy and hydrogen fuel energy is increasingly high. A novel scheme was proposed from liquid hydrogen production by surplus wind and solar energy, to liquid hydrogen-electricity hybrid energy transmission for railway transportation. The 100 MW hybrid energy transmission pipeline was designed with the 10 kA/1.5 kV superconducting DC cable for electricity and cryogenic layers for liquid hydrogen and liquid nitrogen, showing strong capability in transmitting "electricity + cold energy + chemical energy" simultaneously. Economic evaluation was performed with respect to the energy, equipment capacity, and costs, with sensitivity and profitability analysis. With the discount rate 8%, the dynamic payback period of the hybrid energy pipeline was 7.1 years. Results indicated that the shortest dynamic payback period of the hybrid energy pipeline was 4.8 years, with the maximum transmission distance 93 km. Overall, this article shows the novel concept and design of liquid hydrogen-electricity hybrid energy pipelines, and proves the technical and economic feasibilities for future bulk hybrid energy transmission for railway transportation.