Liquid Organic Hydrogen Carriers (LOHCs) present a promising solution for cross-border hydrogen trade by addressing key challenges in transportation and handling. These carriers store hydrogen through chemical bonding with organic compounds, enabling safe and efficient long-distance transport using existing fossil fuel infrastructure. The technology relies on reversible hydrogenation and dehydrogenation processes, which allow for repeated cycles of hydrogen loading and release. While LOHCs offer advantages such as ambient condition storage and compatibility with conventional tankers, they also face limitations, including energy penalties and the need for specialized catalysts.

The chemical process begins with hydrogenation, where hydrogen gas reacts with an unsaturated organic compound in the presence of a catalyst. Common LOHC candidates include toluene-methylcyclohexane, dibenzyltoluene-perhydro-dibenzyltoluene, and naphthalene-decalin systems. For example, toluene (C7H8) undergoes hydrogenation to form methylcyclohexane (C7H14), storing six hydrogen atoms per molecule. This reaction is exothermic, typically releasing 65-70 kJ/mol of hydrogen, and operates at moderate temperatures (100-200°C) and pressures (30-50 bar). The hydrogenated LOHC is then transported in liquid form at ambient conditions, eliminating the need for cryogenic temperatures or high-pressure containment.

Dehydrogenation reverses the process, releasing hydrogen gas and regenerating the original organic compound. This step is endothermic, requiring significant energy input—often between 70-90 kJ/mol of hydrogen—and elevated temperatures (250-300°C) with catalysts such as platinum or palladium supported on alumina or carbon. The energy demand for dehydrogenation is a major drawback, as it reduces the overall efficiency of the hydrogen supply chain. Additionally, the organic carrier must be carefully purified to prevent catalyst degradation, adding operational complexity.

Scalability is a critical factor for LOHC-based hydrogen trade. Unlike liquefied hydrogen (LH2), which demands energy-intensive cryogenic cooling to -253°C, or ammonia (NH3), which requires high-pressure synthesis and cracking, LOHCs leverage existing liquid fuel logistics. Tanker ships, railcars, and trucks designed for oil derivatives can transport hydrogenated LOHCs without modification. This reduces capital expenditure compared to building dedicated LH2 or NH3 infrastructure. However, the volumetric hydrogen density of LOHCs is lower—typically 50-60 kg/m³ compared to ammonia’s 120 kg/m³ and LH2’s 70 kg/m³—leading to higher transport costs per unit of hydrogen delivered.

Energy efficiency further differentiates LOHCs from alternatives. The round-trip efficiency (hydrogen to hydrogen) for LOHC systems ranges between 50-60%, factoring in hydrogenation, transport, and dehydrogenation losses. Ammonia-based trade achieves 60-70% efficiency but faces challenges in cracking NH3 back into hydrogen, while LH2 suffers from boil-off losses during transit, yielding 60-75% efficiency depending on distance. LOHCs avoid these issues but incur higher thermal energy costs during dehydrogenation.

Pilot projects and commercial initiatives demonstrate the viability of LOHCs for international trade. Japan’s Chiyoda Corporation developed the SPERA Hydrogen system, using dibenzyltoluene as a carrier. In 2020, a pilot project successfully transported hydrogen from Brunei to Japan, proving the concept’s feasibility. Germany’s Hydrogenious LOHC Technologies has partnered with global energy firms to deploy large-scale storage and transport solutions, including a collaboration with Mitsubishi for transcontinental hydrogen supply chains. South Korea’s Hyundai Heavy Industries is exploring LOHCs for maritime hydrogen logistics, aiming to integrate them into regional clean energy networks.

Despite these advances, challenges remain. The energy penalty of dehydrogenation limits LOHCs to regions with access to low-cost heat sources, such as industrial waste heat or renewable energy. Catalyst costs and degradation also impact long-term economics. In contrast, ammonia benefits from established global trade networks and higher hydrogen density, while LH2 offers purity advantages for applications like fuel cells.

LOHCs occupy a niche in hydrogen trade, particularly where safety, infrastructure compatibility, and moderate-scale distribution are prioritized. Their scalability depends on advancements in catalyst durability, process intensification, and integration with renewable energy systems. As pilot projects transition to commercial operations, LOHCs could complement ammonia and LH2 in a diversified global hydrogen market. The choice between carriers will hinge on specific trade routes, end-use requirements, and regional energy cost structures.

The development of standardized LOHC systems and international regulations will further influence adoption. Unlike ammonia, which has well-defined safety protocols, or LH2, which builds on aerospace experience, LOHCs require new frameworks for handling, spill management, and quality control. Collaborative efforts between governments and industry players are essential to address these gaps and unlock the full potential of LOHC-based hydrogen trade.

In summary, LOHCs offer a pragmatic pathway for cross-border hydrogen exchange, balancing trade-offs between safety, infrastructure utilization, and energy efficiency. While not a universal solution, they provide a viable alternative in scenarios where other carriers face technical or economic barriers. Continued innovation and scaling will determine their role in the emerging hydrogen economy.