The role of hydrogen for the defossilization of the German chemical industry.

Within the European Green Deal, the European industry is summoned to transform towards a green and circular economy to reduce CO 2 -emissions and reach climate goals. Special focus is on the chemical industry to boost recycling processes for plastics, exploit resource efficiency potentials, and switch to a completely renewable feedstock (defossilization). Despite common understanding that drastic changes have to take place it is yet unknown how the industrial transformation should be accomplished. This work explains how a cost-optimal defossilization of the chemical industry in the context of national greenhouse gas (GHG) mitigation strategies look like. The central part of this investigation is based on a national energy system model to optimize the future energy system design of Germany, as a case study for a highly industrialized country. A replacement of fossil-based feedstocks by renewable feedstocks leads to a significant increase in hydrogen demand by +40% compared to a reference scenario. The resulting demand of hydrogen-based energy carriers, including the demand for renewable raw materials, must be produced domestically or imported. This leads to cumulative additional costs of the transformation that are 32% higher than those of a reference scenario without defossilization of the industry. Fischer-Tropsch synthesis and the methanol-to-olefins route can be identified as key technologies for the defossilization of the chemical industry. • Defossilization is a stringent constraint in addition to GHG mitigation. • Non-energetic demand is satisfied by green hydrogen and its derivatives. • Chemical recycling and the MTO route can be identified as critical technologies. • Defossilizing the German industry doubles the industrial hydrogen demand in 2050. • Cumulative costs of transformation of a defossilized energy system increase by 32%. [ABSTRACT FROM AUTHOR]