Flexibility exploitation in Net-Zero Energy Factories. A technical and economic study case for dairy systems located in Central and South Europe

The decarbonization of energy systems (electric, thermal, gas, and transportation) requires flexibility to integrate power generated by volatile and renewable energy sources (vRES). Industrial systems can contribute to exploiting the flexibility needed to integrate the electricity generated by vRES into energy systems. Designing industrial systems as Net-Zero Energy Factories (NZEF) offers the possibility of exploiting the flexibility that could be used internally to integrate the power generated by renewable energy sources. This study addresses, on one hand, the presentation of a methodology to identify and quantify the flexibility potential of continuous processes typical in dairy systems. On the other hand, it aims to demonstrate a methodology for designing additional flexibility options to operate dairy systems as NZEF. A model has been developed in which the energetic and material flows of conventional diary systems are simulated. The model allows for the design of conventional dairy systems as NZEF and the evaluation of their potential to exploit flexibility. Two different European climate zones have been investigated: Bari (Italy) and Magdeburg (Germany). This study is relevant for designers and facility managers who are following their decarbonization plans, aiming to operate their industrial facility as Net-Zero Energy. The results of this study show that for dairy systems designed as Net-Zero Energy Factories and located in southern Europe (Bari, Italy), the operational costs are much lower than those operating in central Europe (Magdeburg, Germany). Specifically, integrating an 800 kW PV system reduced operational costs by 16.3 % in Bari, compared to 3.8 % in Magdeburg. Additionally, achieving 97 % vRES integration in Bari requires a 1000 kWh thermal storage capacity, whereas in Magdeburg, a 500 kWh capacity is sufficient. These findings suggest that NZEF designs can be optimized based on regional climatic conditions to maximize cost efficiency and vRES integration. The analysis indicates that sensible heat storage systems should be preferred over electrochemical batteries when designing additional flexibility options, considering both technical and economic criteria.