Design of a 75 km GW-class Hybrid Pipeline for the Synergetic Transmission of Liquid Hydrogen and Electrical Energy by High-Temperature Superconductivity

The transmission infrastructure for both electrical energy and hydrogen must be significantly expanded in Germany to enable climate neutrality. A hybrid pipeline can transmit both energy vectors simultaneously, efficiently, and compactly. Hybrid pipelines exploit the synergy provided by liquid hydrogen, which is used as a coolant and energy carrier, and high-temperature superconductors for the transmission of electrical energy. We present the conceptual design of a 75 km long GW-class hybrid pipeline for operation without intermediate cooling stations between Brunsbüttel and Hamburg in northern Germany. The design is based on a rare-earth barium copper oxide (REBCO) direct current cable and a thermally insulated rigid smooth pipe. We examine the electrical topology, cable build-up, cable behavior in the case of a short circuit, and the thermal-hydraulic design. The results lead to a hybrid pipeline with an outer diameter of less than 45 cm that can transmit 0.55 to 1.14 GWt of liquid hydrogen, and two parallel coaxial monopoles that transmit 4 GWe of electrical energy. Future research will build on the presented design to unveil the techno-economic competitiveness of this technology compared with conventional transmission alternatives.