Water intensity for hydrogen production with and without carbon capture and sequestration

Low-carbon hydrogen has gained significant attention, particularly in nations with abundant fossil fuel reserves. While the techno-economic and greenhouse gas (GHG) emission performance of hydrogen production with carbon capture and storage (CCS) is well understood, its impact on water demand remains underexplored. This study evaluates water demand, including water withdrawal, consumption, and discharge, in hydrogen production via steam methane reforming (SMR), auto-thermal reforming (ATR), and natural gas decomposition (NGD), both with and without CCS. CO 2 is captured using commercially available amine scrubbing technology and transported via CO 2 pipelines. Three SMR-CCS configurations were analyzed: SMR-52% (52% CO 2 capture from syngas), SMR-85% (85% CO 2 capture from syngas and flue gas in separate units), and SMR-86% (86% CO 2 capture from syngas and flue gas in one integrated unit). Water withdrawal values (L/kg-H 2 ) for SMR, ATR, catalytic-thermal NGD, plasma NGD, SMR-52%, SMR-85%, SMR-86%, ATR-CCS, and catalytic-thermal NGD-CCS are 10.29, 14.27, 5.37, 22.57, 12.10, 18.41, 23.36, 16.98, and 7.32, respectively. Water consumption values are 5.34, 9.33, 4.30, 16.73, 6.91, 11.01, 14.43, 11.69, and 5.68 L/kg-H 2 , respectively. Hydrogen production efficiency was evaluated through net energy ratios (NERs), which range from 0.43 to 0.76. The findings indicate that CCS increases water demand while reducing overall hydrogen production efficiency. These results provide valuable insights for policymakers and industry stakeholders, helping identify challenges and opportunities for sustainable hydrogen deployment, particularly in water-scarce regions. • We studied the water demand of hydrogen production via natural gas-based technologies • Water withdrawal values range from 5.37 to 23.36 L/kg-H 2 • Water consumption values range from 4.30 to 16.73 L/kg-H 2 • The CCS unit increases hydrogen plant water use and reduces energy efficiency • The net energy ratio ranges from 0.43 to 0.76