Assessing the water-energy-carbon nexus (WECN) in combined cycle power plants in Iran

Water and energy are two vital and related resources and the process of generation and distribution of these resources in the electricity industry leads to carbon emissions and climate change. The study aimed to evaluate the water, energy, and carbon nexus (WECN) in the combined cycle power plants. First, carbon and water footprints were estimated by the LCA method. Then, the WEN and flow relations were investigated using the REWSS (Regional Energy & Water Supply Scenarios model) model and the Sankey diagram. Finally, optimal relationships between WEN were defined using Vensim software to increase electricity production along with managing water consumption and reducing greenhouse gas emissions. The result of WECN in this study showed that the average annual amount of water footprint in electricity generated was 980 L of water consumed per MWh of electricity. The highest and lowest water footprint was related to the Damavand (67.14 L/MWh) and Zavareh (18.95 L/MWh) power plants, respectively. Moreover, the average annual amount of carbon footprint in electricity generated was 0.623 t/mkWh of electricity. The highest and lowest average carbon footprint was related to Fars (1.15 t/mkWh) and Khoy (0.53 t/mkWh) power plants, respectively. Further, the highest (1898 kcal/kWh) and lowest (1704 kcal/kWh) thermal efficiency was determined for Khoy and Gilan power plants, respectively. The comparison of WEN results showed that the amount of electricity generation, water consumption, and carbon emissions in combined cycle power plants are not always directly related to each other. The results can help managers and politicians in planning and integrated managing of these limited resources.