Long-term energy transition pathways for low-carbon heating and cooling in Iran

Introduction: The heating and cooling sector accounts for a substantial share of energy consumption and greenhouse gas emissions, making it a priority for national energy transition strategies. Although numerous studies have investigated low-carbon heating and cooling technologies in European countries, comprehensive scenario-based assessments of the long-term transition of Iran’s distributed heating and cooling sector remain limited. In particular, there is a lack of integrated analyses that simultaneously evaluate individual efficiency measures, district energy systems, and renewable energy technologies within a national energy system framework. This study aims to evaluate long-term energy transition pathways for Iran’s distributed heating and cooling sector and identify the most effective strategy for reducing primary energy consumption and carbon dioxide (CO2) emissions while improving overall system efficiency. Materials and methods: Iran’s heating and cooling system was modeled using EnergyPLAN version 12.6 based on national energy balance data, electricity demand, fuel consumption statistics, and technical parameters for the base year 2021–2022. Four transition scenarios were developed and simulated over a 20-year planning horizon: (i) Business as Usual, (ii) Individual Energy Approach, (iii) Integrated System Approach, and (iv) Combined Approach. The scenarios were compared in terms of primary energy consumption, CO2 emissions, energy efficiency, and overall system performance. Results: The simulations indicate that the Combined Approach outperforms all other scenarios. Compared with the Business-as-Usual scenario, it reduces CO2 emissions from approximately 200 Mt to 60 Mt (70% reduction) and decreases primary energy consumption from 845 TWh to 180 TWh (an approximately 79% reduction). The integrated deployment of heat pumps, district heating, combined heat and power (CHP), solar thermal systems, photovoltaic generation, and wind energy substantially improves system efficiency while reducing dependence on fossil fuels. Conclusions: The findings demonstrate that combining demand-side efficiency improvements with integrated energy infrastructure and renewable energy deployment provides the most effective pathway for decarbonizing Iran’s heating and cooling sector. The proposed framework offers quantitative evidence to support national energy transition planning and provides policy-relevant insights for other fossil fuel-dependent countries pursuing low-carbon heating and cooling strategies.