Chemical storage of hydrogen in synthetic liquid fuels: building block for CO2-neutral mobility

Green hydrogen is anticipated to play a major role in the decarbonization of the mobility sector. Its chemical storage in CO2-neutral synthetic liquid fuels is advantageous in terms of safety and reliability compared to other hydrogen storage developments, and thus represents a complementary building block to developments in electric and hydrogen mobility for the low-carbon transition in the mobility sector. Its development is especially relevant for transport sectors which will have no alternatives to liquid fuels in the foreseeable future. In this paper, three alternative technological routes for the chemical storage of hydrogen in CO2-neutral synthetic liquid fuels are identified and comparatively evaluated in terms of feedstock potential, product potential, demand for renewable electricity and associated costs, efficiency as well as expected market relevance. While all three routes exhibited similar levels of overall efficiencies, electricity-based liquid fuels in Germany are currently limited by the high cost and limited supply of renewable electricity. In contrast, liquid fuels generated from biogenic waste have a constant supply of biogenic feedstock and are largely independent from the supply and cost of renewable electricity.