Value chain analysis for long-distance transport of low-carbon energy: Liquefied hydrogen, ammonia, and LNG

Abstract

Economically transporting low-carbon energy to resource-poor regions is essential to achieving a hydrogen economy for a sustainable society. Recently, liquefied hydrogen and ammonia have gained attention as hydrogen carriers. The aim of this study is to compare the greenhouse gas intensities and costs of liquefied hydrogen and ammonia supply chains as energy carriers for blue hydrogen. Additionally, this study compares these two supply chains with the existing liquefied natural gas supply chain. Accordingly, life cycle and techno-economic assessments are performed based on the analysis of material and energy balance data for the three supply chains. As a result, liquefied hydrogen shows improvements of approximately 7% and 15% over ammonia in terms of greenhouse gas intensity and cost, respectively. However, if ammonia is used directly as a fuel rather than being converted to hydrogen, the ammonia supply chain demonstrates improvements of approximately 13% and 15% in terms of greenhouse gas intensity and cost, respectively, compared to the liquefied hydrogen supply chain. In comparison to the liquefied natural gas supply chain, both liquefied hydrogen and ammonia offer little advantage in terms of greenhouse gas intensity, primarily due to significant indirect greenhouse gas emissions associated with the blue hydrogen production. From a cost perspective, liquefied natural gas holds a significant advantage. These results provide insights into the need for improvements in process efficiency and the supply of clean energy for a sustainable hydrogen economy and highlight that the choice of an appropriate hydrogen carrier can vary depending on the end user.