Electrochemical concentration cells for produced water valorization: techno-economic and environmental assessment in Gulf of Suez oilfields

Abstract

Produced water is the largest waste stream in oilfield operations and is commonly managed as a disposal burden despite its high salinity and large volume. This study evaluates whether the salinity gradient between Gulf of Suez produced water and seawater can be used for auxiliary electricity generation through electrochemical concentration cells (ECCs). Formation-water samples from four Gulf of Suez oilfields were characterized for salinity, temperature, pH, and ionic composition, and the measured data were used in electrochemical, techno-economic, and environmental assessment models under field-relevant operating scenarios. The modeled ECC voltage ranged from 19 to 37 mV per cell, requiring 329–541 cells to achieve a 12 V stack, while the estimated specific energy yield ranged from 0.55 to 0.80 kWh m⁻³ of processed brine, corresponding to approximately 450–4,000 kWh day⁻¹ depending on field flow rate. The calculated levelized cost of electricity was 0.06–0.10 USD kWh⁻¹, and the estimated greenhouse-gas offset reached 2.2–3.6 t CO₂ day⁻¹ per field under the modeled diesel-displacement scenarios. The novelty of this work lies in combining real produced-water chemistry from Gulf of Suez oilfields with ECC performance modeling and integrated techno-economic and environmental assessment for oilfield-specific deployment. Overall, the results indicate that produced-water valorization through ECCs may provide a promising route for auxiliary low-carbon power generation in oilfields, while also highlighting the need for further pilot-scale validation, long-term membrane performance assessment, and refined life-cycle boundaries.