State-of-art of Liquid Hydrogen Carriers: Trends in the Selection of Organic Molecules

Abstract: Nowadays, fossil fuels represent the main energy source. According to the BP Statistical Review of World Energy report, in 2021, global energy consumption amounted to 595.15 EJ of which 82% was generated from natural gas, oil and coal. The energy consumption growth, rapid depletion of fossil fuels and increasing pressure on the environment threaten the continued sustainability of the global energy system. In this context, renewable energy sources (RES), which now account for 6.7% are attracting increasing attention. The key obstacles to the introduction of RES (solar, wind geothermal, etc.) are their nonstationarity due to seasonality, meteorology and differences in geoclimatic conditions. In this regard, an important role is played by the development of technologies for efficient storage and transportation of renewable energy to consumers. One of the most promising storage technologies is the processing of renewable energy into hydrogen, which, due to the high mass energy intensity (120 MJ⋅kg-1) and environmental friendliness, can be considered a promising energy carrier. Nevertheless, the widespread use of hydrogen as a fuel is limited due to the low volumetric energy density and high explosiveness. Thus, along with the development of technologies for processing renewable energy sources into hydrogen (e.g., electrolysis), a large number of studies are focused on the development of technologies for storage and transportation. This study provides a brief overview of the state of the art of these technologies, with a focus on technology based on the use of liquid organic hydrogen carriers (LOHCs).