Perspective on Decarbonizing Long-Haul Trucks Using Onboard Dehydrogenation of Liquid Organic Hydrogen Carriers

Abstract

Decarbonization of long-haul trucks, which are the backbone of global supply chains, is necessary to meet climate goals. Currently, battery electric and conventional hydrogen powertrains are not cost-competitive solutions against diesel. Liquid Organic Hydrogen Carriers (LOHCs) are a promising fuel option that benefits from synergies with existing retail fuel distribution infrastructure, providing a cost-effective way to transport hydrogen energy. LOHCs are now used to deliver hydrogen gas to refueling stations, where it is then compressed and used to fuel trucks. However, this approach incurs ∼50% energy loss from the endothermic dehydrogenation and compression of hydrogen. We discuss an alternative concept based on onboard hydrogen release to address these pain points. We highlight recent advances in dehydrogenation reactor design, catalyst technologies, and hydrogen combustion engines that are relevant to the proposed system. Deficiencies in current technologies are discussed, along with potential research directions to address them. Initial analysis shows that the LOHC option, charged with blue hydrogen, achieves rough cost parity with diesel. The estimated well-to-wheel greenhouse gas emissions for this option are approximately one-third of diesel. Based on our analysis, LOHC-powered trucks featuring onboard dehydrogenation are a promising option to decarbonize long-haul trucking. However, making this option a reality will require dedicated study and development of core components for the power-dense, efficient, and robust onboard release of hydrogen from LOHCs along with efficient heat integration between the engine and the dehydrogenation reactor.