Energy Technology, 2024. 2301526 ISSN 21944288.

Verfügbar unter: https://onlinelibrary.wiley.com/doi/epdf/10.1002/ente.202301526

The transition of the German economy and energy system toward CO₂ neutrality requires large quantities of climate-friendly chemical energy carriers, such as green hydrogen, to be imported. The decision on the most favorable import routes must consider its energy efficiency To respect the remaining CO₂ budget to achieve the 1.5° climate target, the implementation time and therefore additional evaluation criteria must be taken into account. In this article, as a first step, the energy utilization rate (ñ) for different hydrogen import options is evaluated. Starting off from hydrogen at 25 °C and 25 bar produced in the exporting country, liquid hydrogen, ammonia, liquid methane (Green LNG), methanol, and liquid organic hydrogen carrier are considered as chemical energy carries. Liquid hydrogen is in future the most efficient import option ( ñ= 7%) when gaseous hydrogen is supplied in the importing country. When direct utilization of the H₂ derivatives is considered, the ammonia import route has the highest energy utilization rate with 77%. If point sources for CO₂ are considered, direct utilization of methanol ( ñ= 83%) and Green LNG ( ñ= 76%) are energetically favorable import options. Additional significant criteria for a technological assessment are maturity of technologies, available capacities, infrastructures, and production processes.