Comparison of Liquified Gas Energy Carriers and Conventional Fossil Fuels with a Focus on Storage Requirements for the Use in Mobile Applications

Authors

Dipl.-Ing. Dr. T. Stepan, Dipl.-Ing. T. Breiteneder, Dipl.-Ing. (FH) Dr. J. Winklhofer, SAG Innovation GmbH, Lend:

Year

2023

Print Info

Production/Publication ÖVK

Summary

The large-scale deployment of CO2-neutral, alternative fuels is a key element to achieve decarbonization of the transport sector. In this paper, the usage of liquified gases as fuels, in particular LH2, LNG and NH3, is evaluated in terms of storage requirements, and compared with methanol and conventional fossil fuels as a benchmark. In addition, the well to wheel efficiency of these fuels, based on sustainable (“green”) production, is considered. With regards to storage density, the use of highly insulated containers, required for cryogenic storage, is detrimental to both gravimetric as well as volumetric density of the storage system. As such, LH2 fuel tanks feature the lowest storage density (1.5 kWh/L), followed by NH3 (2.5 kWh/L) and LNG (3.9 kWh/L). Methanol fuel tanks exhibit a comparable energy density to LNG, whereas Diesel tanks feature double the storage density of methanol (8.2 kWh/L). In terms of storage system costs, the evaluated solutions can be divided into 3 groups. Cryogenic storage is most expensive, followed by mild cryogenic storage of ammonia. Conventional storage of methanol or diesel is least expensive, featuring only 2-5 % of costs compared to a LNG storage system. In terms of energy efficiency, “green” production of alternative fuels with electricity consumes around 36 to 50 % of the energy content of the fuel itself. Since hydrogen is the precursor for all evaluated alternative fuels, the use of LH2 as fuel is the most efficient option, due to the lack of subsequent conversion processes during production. However, large scale liquefaction and transportation of hydrogen are yet to be implemented.

ISBN

978-3-9504969-2-5