Evaluating the Environmental Costs of Electricity Generation in Tehran through a Combined Thermal-Solar System using the Water-Energy-Environment Nexus Approach

Background and Aim: The environmental consequences of fossil fuel reliance, combined with the rising energy demand in urban centers, have prompted interest in combined thermal-solar power systems as a sustainable approach to electricity generation. Tehran, which depends heavily on thermal power plants, faces significant challenges from high greenhouse gas emissions, substantial water consumption, and increasing environmental costs. This study aims to assess the environmental costs of electricity generation through a combined thermal-solar system and compare it with thermal-only systems. Three major power plants—Tarasht, Montazer Ghaem, and Besat—were selected as case studies. The Water-Energy-Environment Nexus (WEE Nexus) approach was employed to analyze interactions between water and energy resources in these systems.
Materials and Methods: The study utilized the Life Cycle Assessment (LCA) method to evaluate environmental impacts, focusing on the reduction of greenhouse gas emissions and water consumption. Data on fuel consumption, emissions, and water use were gathered from official reports and validated databases. For combined system modeling, SimaPro software was used, while SPSS was employed for data analysis. Independent T-tests and ANOVA were performed to assess the statistical significance of differences between the two scenarios (base and combined). The WEE Nexus approach was applied to evaluate the simultaneous reduction of water consumption and emissions.
Results and Discussion: The analysis revealed substantial environmental advantages of integrating solar energy with thermal systems across all three plants. The results indicate that the combined thermal-solar system significantly reduced greenhouse gas emissions, water consumption, and environmental costs in all three power plants. In Montazer Ghaem Power Plant, CO2 emissions decreased by 28.1%, water consumption was reduced by 26.5%, and environmental costs dropped to $195.67 per gigawatt-hour, showing the best performance among the studied plants. The Besat Power Plant also showed significant reductions in emissions and water use, though slightly less than Montazer Ghaem due to lower solar irradiance. Tarasht Power Plant performed weaker than the others because of older equipment and lower efficiency. Statistical analysis using independent T-tests confirmed that the differences between the base and combined scenarios across all plants were statistically significant (p < 0.05). The WEE Nexus approach revealed that reducing water consumption through the incorporation of solar energy in thermal systems not only decreased emissions but also alleviated pressure on water resources, which is crucial for water-scarce areas like Tehran. The findings highlight the potential of solar energy as a complementary source for improving environmental sustainability in electricity generation.
Conclusion: This study demonstrates that using combined thermal-solar systems in Tehran’s power plants can significantly reduce greenhouse gas emissions, water consumption, and environmental costs. Among the three plants, Montazer Ghaem performed the best due to favorable geographical conditions, modern equipment, and higher solar irradiance. The findings underline the importance of applying the WEE Nexus approach in energy planning to optimize water and energy management and reduce dependence on fossil fuels. Future recommendations include investing in upgrades for older plants such as Tarasht to enhance efficiency, as well as expanding the solar component of combined systems. These actions could further reduce environmental impacts and provide a scalable model for similar metropolitan regions facing energy and resource challenges.