Geospatial life cycle assessment of blue hydrogen production pathways : case study of the Marcellus shale and Permian basin

Date
2023-04-24
Authors
Vallejo Vargas, Sandra Valeria
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Abstract

Blue hydrogen is considered one of the numerous potential pathways to achieve net-zero climate targets for a decarbonized world. While recent studies have shown a wide range in greenhouse gas (GHG) emission impact of blue hydrogen, geospatial differences remain unclear. This is especially important as recent studies have shown significant differences in methane emissions across oil and gas basins, facility types, and operators. This work develops a geospatial life cycle assessment (LCA) model to estimate GHG emissions of different blue hydrogen production pathways. Two case studies are evaluated: blue hydrogen production in Texas with gas from the Permian basin, and in Ohio with gas from the Marcellus shale. The main finding is that producing hydrogen from Permian basin-derived gas has life cycle GHG emissions intensity of ~7.4 kg CO₂e/kg H₂, which is more than twice the emissions intensity associated with blue hydrogen production using natural gas sourced from the Marcellus shale (~3.3 kg CO₂e/kg H₂). Recently, the Inflation Reduction Act in the United States includes tax credit provisions for hydrogen production based on achieving life cycle emissions intensity below 4 kg CO₂e/kg H₂. The results from this work indicate that only one of these U.S. case scenarios might qualify as low-carbon hydrogen without further reduction in methane leakage or increase in carbon capture rate when a full life cycle assessment from the well to the carbon capture and storage (CCS) facility is considered. The impacts of methane leakage rate and carbon capture efficiency are investigated through a sensitivity analysis to develop benchmarks for hydrogen production that would qualify for the tax credit. Finally, this research provides insights into the environmental implications of blue hydrogen compared to other low-carbon hydrogen production technologies such as green hydrogen.

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