Energy and exergy flows of a hydrogen supply chain with truck transportation of ammonia or methyl cyclohexane

Reductions of fossil fuel consumption and greenhouse gas emissions are possible with hydrogen fuels derived from renewable energy sources. Power fluctuations of a transmission network can be controlled using hydrogen carriers, but the efficiency of hydrogen energy supply chains has so far made them economically infeasible. Ammonia (NH3) and methyl cyclohexane (MCH) can be transported using existing liquid-fuel infrastructure. This study models the energy and exergy flows for an entire hydrogen-energy supply chain using NH3 or MCH. These models suggest that the total efficiency of an NH3 system can be 22.5% and the total efficiency of an MCH system can be 18%, with heat-to-power ratios of 0.935 and 0.931, respectively. The analysis quantifies the improvements that can be gained with technological interventions at key points of each supply chain. (C) 2019 Published by Elsevier Ltd.