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Title: Life cycle greenhouse gas emissions of hydrogen fuel production from chlor-alkali processes in the United States

Journal Article · · Applied Energy
 [1];  [1];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Energy Systems Division

By-product hydrogen from chlor-alkali processes can help meet the increasing demand for hydrogen fuel in early fuel cell electric vehicle markets (e.g., California) in the U.S. Hydrogen produced from chlor-alkali plants is typically combusted for process heat on site, vented to the atmosphere (i.e., wasted), or sold to the external merchant hydrogen market. Whether it is combusted, vented, or sold as a commodity, relevant information is lacking as to the life-cycle environmental benefits or trade-offs of using by-product hydrogen from chlor-alkali plants. A life-cycle analysis framework was employed to evaluate well-to-gate greenhouse gas (GHG) emissions associated with by-product hydrogen from chlor-alkali processes in comparison with hydrogen from the conventional centralized natural gas steam methane reforming (central SMR) pathway. U.S.-specific, plant-by-plant, and up-to-date chlor-alkali production characteristics were incorporated into the analysis. In addition to the venting and combustion scenarios, to deal with the multi-functionality of the chlor-alkali processes that simultaneously produce chlorine, sodium hydroxide, and hydrogen, two different co-product allocation strategies were adopted mass allocation and market value allocation. It was estimated that by-product hydrogen production from chlor-alkali processes creates 1.3-9.8 kg CO2e/kg H2 of life-cycle GHG emissions on average, which is 20-90% less than the conventional central SMR pathway. The results vary with co-product treatment scenarios, regional electric grid characteristics, on-site power generation, product prices, and hydrogen yield. Despite the variations in the results, it was concluded that the life-cycle GHG emission reduction benefits of using by-product hydrogen from chlor-alkali processes are robust. In conclusion, with a diverse set of scenario analyses, the study developed a comprehensive and detailed life-cycle GHG emissions inventory of the chlor-alkali by-product hydrogen pathway and quantified sensitivity indices in the context of different assumptions and input parameter values.

Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation and Fuels. Hydrogen and Fuel Cell Technologies Office (HFTO)
Grant/Contract Number:
AC02-06CH11357
OSTI ID:
1461466
Alternate ID(s):
OSTI ID: 1991446
Journal Information:
Applied Energy, Vol. 217, Issue C; ISSN 0306-2619
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 58 works
Citation information provided by
Web of Science

References (6)

Life cycle assessment of wind-based hydrogen production in Western Canada journal June 2016
Hydrogen mobility from wind energy – A life cycle assessment focusing on the fuel supply journal November 2016
Fuel cell cars in a microgrid for synergies between hydrogen and electricity networks journal April 2017
Cleaner chlorine production using oxygen depolarized cathodes? A life cycle assessment journal October 2014
Life Cycle Assessment model for the chlor-alkali process: A comprehensive review of resources and available technologies journal October 2017
Avoiding Co-Product Allocation in Life-Cycle Assessment journal June 2000

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Figures / Tables (10)