Research on Portfolio Strategies for Low-Carbon Transition Pathways in Electricity-Heat Nexus Systems Incorporating Multi-Device Integrated Systems

Driven by the “Dual Carbon” objectives, integrated energy systems face an imperative to achieve synergistic optimization encompassing economic viability, low-carbon performance, and operational flexibility. To facilitate the low-carbon transition of combined heat and power (CHP) units, this study proposes an integrated optimization framework coupling CHP with diversified auxiliary installations. A multi-dimensional comprehensive evaluation is conducted on distinct coupling configurations incorporating electric boilers, heat pumps, thermal energy storage, and carbon capture and storage. Initially, an electro-thermal optimization model integrating multi-component devices—including CHP with carbon capture and storage (CHP-CCS), electric boilers, heat pumps, and thermal energy storage—is developed. A comprehensive evaluation index system is established across four dimensions: economic efficiency, operational flexibility, low-carbon performance, and technology readiness level. Subsequently, the Tanimoto coefficient is introduced to supersede the Euclidean distance in the conventional Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) methodology, thereby refining the similarity measurement approach for optimal solution selection. Collectively, the configuration integrating CHP-CCS with electric boilers and heat pumps emerges as the optimal pathway. This configuration ensures reliable electricity and thermal load supply while substantially reducing system-level low-carbon transition costs and carbon emissions, concurrently enhancing renewable energy accommodation capacity.