Sustainable hydrogen production from flare gas and produced water: A United States case study

Gas flaring and produced water (PW) emissions are common environmental challenges with significant impacts on the oil production industry. This study proposes a novel approach to address these concerns by developing energy self-sufficient networks for simultaneous utilization of flare gas (FG) and PW for sustainable hydrogen production. Three distinct scenarios are analyzed: hydrogen production without CO2 2 capture (Hydra), fossil fuel- based (FF) hydrogen production with CO2 2 capture and utilization in enhanced oil recovery (HydraCap-FF), and a solar-thermal-assisted HydraCap-FF system (HydraCap-RE). Techno-economic and environmental models are constructed for each scenario's optimal configuration, enabling a comparative analysis of their economic viability and environmental impact. Additionally, the designed systems are examined through a flexibility analysis to evaluate input materials and their influence on the system's viability. Results highlight the promising potential of HydraCap-RE, achieving significant reductions in CO2 2 emissions and water footprint compared to traditional methods. The HydraCap-RE generates hydrogen with the cost of 2.86 $/kg H 2, hydrogen yield of 31.25 kg H2/100 2 /100 kg FG, specific emission of 0.86 kg CO2/kg 2 /kg H2 2 and water footprint of 0.185 kg H2O/kg 2 O/kg H2. 2 . Moreover, the flexibility analysis indicates that an optimal FG/PW ratio of 0.53 yields the highest economic value. The results demonstrate that deploying HydraCap-FF in the Permian, Bakken, and Eagle Ford shale regions can produce 0.807, 0.454, and 0.121 million tons of hydrogen annually, respectively, and reduce CO2 2 emissions by 6.37, 3.58, and 0.956 million tons, respectively. Furthermore, the HydraCap-RE deployment in these shale fields outperformed, with 17 % higher hydrogen production and 28.42 % lower CO2 2 emissions. These findings provide valuable insights for decision-makers seeking to reduce CO2 2 emissions the oil and gas industries and providing clean and sustainable products for these areas.