Resilience optimization of multi-modal energy supply systems: Case study in German metal industry

The energy-intensive industry sector, including the metal industry, strongly depends on resilient energy supply concepts. Environmental concerns, e.g. about the future availability of groundwater for cooling, force companies to analyze the resilience of their energy supply systems. The use of heat pumps, electrolysers and combined heat-and-power units couples multi-modal supply systems for electricity, thermal demands, and process gases. This paper presents an integrated design approach for industrial supply systems showcased for a real-world case of a German copper mill. System resilience is evaluated for both environmental risk mitigation and technical robustness. Quantitative results reveal heat pumps as an attractive technology option: Groundwater withdrawal for cooling is cost-efficiently reduced by 18%, whereas the waste heat can be utilized to meet more than 70% of the space heating demand. This enhances system resilience to a future tightening of the regulatory environment for water withdrawal and increasing carbon prices. The mill experiences only rarely grid outages due to the high reliability of the German power system. Additional distributed generators or storages with the ability of islanding therefore do not appear economically beneficial in this case study.