Liquid organic hydrogen carriers (LOHC): Concept evaluation and techno-economics

Liquid organic hydrogen carriers (LOHC) are a promising solution for the efficient and safe storage and transportation of hydrogen, which have been the main hurdles for the realization of the hydrogen economy. The idea is to bind hydrogen to liquids from which hydrogen can be released reversibly returning the carrier liquid to its original state ready to be hydrogenated again. Although there are already some commercialization activities, LOHC systems are still an emerging technology having only a very limited number of technology providers and pilots. This report aimed to identify the advantages and possible limitations of the LOHC technology and evaluate the feasibility in the Finnish context. While the LOHC concept provides a means to transport and store hydrogen efficiently, safely and without storage losses, the high reaction enthalpies and high temperatures (~300–350 °C) required for releasing hydrogen were identified as possible challenges for the economics. Should hydrogen release be carried out by burning part of the hydrogen, ~30% of the hydrogen would be consumed. The equal amount of heat is released when hydrogen is bound but at lower temperature (~150 °C), and for economic feasibility it is important to find use for this heat. Equally important would be to utilise waste-heat to release the hydrogen but waste-heat with sufficient temperature is not often available. In future, the development of new LOHC compounds having lower reaction enthalpies and new catalysts for decreasing the dehydrogenation temperatures should be targeted. Generally speaking, the applications involving transportation of hydrogen and end-users using hydrogen as a reactant rather than an energy source were seen more economically attractive for the LOHC concept at least in the near-term. In the case studies, the logistics of by-product hydrogen from chlorate and chlor-alkali plants to light industry was identified as a possible low-hanging fruit for the LOHC concept to enter the markets. Also, should the need to import of renewable hydrogen from locations with high potential of renewable energy arise, the LOHC concept was found to be competitive against liquid hydrogen.