Renewable energy integration and modeling approaches in district heating networks: a review

Integrating renewable energy sources (RES) into district heating networks (DHNs) is a promising strategy for achieving global decarbonization goals. This requires an understanding of viable RES options for DHNs to guide context-specific selection. Additionally, investors and operators must assess the performance of RES-based DHNs, necessitating accurate models to support optimal investment decisions and operational strategies. This paper addresses both of these aspects. We present a review of the integration of five selected RES into DHNs, alongside various modeling techniques used to analyze and characterize them. A multi-label classification of modeling approaches is proposed based on a detailed literature review and technological insights. A decision tree is included to help select an appropriate modeling technique based on specific objectives/tasks in DHNs. Furthermore, we discuss the integration pathways for RES in DHNs. Also, a qualitative overview of RES in DHNs is presented across six key criteria: cost, efficiency, storage potential, system complexity, flexibility, and carbon footprint. A multi-criteria overview suggests that hybrid systems seem to offer a more practical and effective solution for integrating RES into DHNs. However, their technical, economic, and environmental performance remains highly context dependent.