Defossilizing the energy and industrial systems and transformation towards a circular economy have versatile impacts on the availability and demand of alternative resources. However, systematic analyses on these interrelations are very sparse. Thus, this paper investigates the interlinkages between the energy transition and the transformation towards a circular economy in Germany. The study is based on material flow analysis models of the steel and cement industries as well as the coal and lignite power plants in order to depict a comprehensive description of the material, energy and emission flows of these sectors and their interdependencies.

The analyses prove the inherent interrelation between energy transition and circular economy. On the one hand, energy transition does not only bear various techno-economic challenges and have substantial effects on the production costs, but it also affects the availability of secondary materials. For instance, the coal phase-out and the introduction of green steel imply that the current supplies of blast furnace slag, fly ash and FGD gypsum cannot be maintained.

On the other hand, circularity approaches can also influence the energy transition. For example, banning single-use plastics and increasing recycling rates of plastics can deprive the cement industry from significant amounts of energy resources with low-carbon footprint. Contrariwise, CO₂ recycling can promote the energy transition by means of mitigating CO₂ emissions via carbonation. Therefore, the study can help policymakers to understand the indirect effects of existing and future policies. Also, it can help to develop future strategies to handle associated impacts and avoid material shortages.

能源和工业系统的去化石化以及向循环经济的转型对替代资源的可用性和需求具有多种影响。然而，对这些相互关系的系统分析非常稀少。因此，本文研究了德国能源转型与向循环经济转型之间的相互联系。该研究基于钢铁和水泥行业以及煤炭和褐煤电厂的物质流分析模型，以全面描述这些行业的物质、能源和排放流及其相互依存关系。

分析证明了能源转型与循环经济之间的内在相互关系。一方面，能源转型不仅面临各种技术经济挑战并对生产成本产生重大影响，而且还影响二次材料的可用性。例如，煤炭的淘汰和绿色钢的引入意味着目前高炉矿渣、粉煤灰和脱硫石膏的供应无法维持。

另一方面，循环方法也会影响能量转换。例如，禁止使用一次性塑料和提高塑料的回收率可能会使水泥行业失去大量低碳足迹的能源。相反，CO ₂回收可以通过碳化减少CO ₂排放来促进能源转型。因此，该研究可以帮助决策者了解现有和未来政策的间接影响。此外，它还可以帮助制定未来的战略来处理相关影响并避免材料短缺。