Assessing technical, economic, and environmental impacts of solar-powered wastewater treatment with battery storage

• Integrated a 250-kW photovoltaic system with 10 kWh battery for wastewater treatment. • System supplies over 50 % of annual energy, reducing grid dependency significantly. • Battery storage smooths solar intermittency ensuring reliable energy supply. • Increasing grid outages from 25 to 300 h significantly increased the capacity of photovoltaic and battery units. This study evaluates the feasibility of integrating photovoltaic solar systems with battery storage for wastewater treatment plants in regions with high solar energy potential, such as Iran, to optimize energy reliability and sustainability. Existing research lacks a comprehensive assessment of wastewater treatment plants and fails to simultaneously address technical, economic, and environmental dimensions. A new 250-kilowatt photovoltaic system coupled with a 10-kilowatt-hour battery storage has been modeled using Hybrid Optimization of Multiple Energy Resources software, addressing solar intermittency and reducing grid dependency. The hybrid system supplies over 50 % of the annual energy demand of the wastewater treatment plant, leading to significant operational cost savings and environmental benefits. Reliance on the electricity grid is substantially reduced, while battery storage effectively mitigates solar energy intermittency, ensuring a reliable power supply. Increasing annual grid outage duration from 25 to 300 h significantly enhances Photovoltaic capacity and the number of lithium-ion batteries. Specifically, Photovoltaic capacity increases from approximately 61.73 kW to 135.47 kW, and the number of 1 kWh lithium-ion batteries grows from 53 to 217 units, indicating a strategic shift toward on-site energy generation and storage. This adaptive sizing reflects the system’s response to increased grid uncertainty, aiming to maintain energy supply reliability during outages. This model provides a replicable solution for regions with similar climates, advancing the water-energy nexus and supporting Sustainable Development Goals 6 (Clean Water) and 7 (Affordable and Clean Energy).