Comparative life cycle analysis on ethylene production from electrocatalytic reduction of carbon dioxide

Journal Article · Mon Feb 19 04:00:00 EST 2024 · Journal of Cleaner Production

DOI:https://doi.org/10.1016/j.jclepro.2024.141348· OSTI ID:2475290

Kim, Taemin ^[1]; Benavides, Pahola Thathiana ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

Ethylene is one of the largest greenhouse gas emitters and the most diversly used commodity chemicals globally. Electrocatalytic reduction of CO₂ to ethylene received great attention from the research society to decarbonize the ethylene production. Here, in this study, a life-cycle analysis is conducted using the Greenhouse Gases, Regulated Emissions, and Energy use in Technologies (GREET) model on the three electrocatalytic CO₂-reduction pathways (or “e-ethylene” pathways): i) cascade conversion via carbon monoxide intermediate; ii) single-step conversion in membrane electrode assembly (MEA); and iii) single-step conversion in alkaline flow cell. The results showed that the electricity consumption is the lowest for the cascade pathway (164 MJ/kg), thus resulting in the lowest cradle-to-gate carbon intensity [18 kgCO₂e/kg with United States (US) average grid)] among the three pathways followed by the single-step MEA (32 kgCO₂e/kg) and then by the single-step alkaline (56 kgCO₂e/kg). However, all three e-ethylene pathways were significantly more carbon-intensive than their fossil-based counterpart (1.1 kgCO₂e/kg) due to their excessive energy consumption with the current state of technology. With renewable electricity, all three pathways yielded negative carbon intensity: from -3.1 kgCO₂e/kg to -1.6 kgCO₂e/kg depending on the source of CO₂. The threshold carbon intensity of electricity (TCIE), defined as the upper bound of the carbon intensity of electricity to achieve lower carbon intensity for e-ethylene compared to fossil-based ethylene, is calculated for both current and future state of e-ethylene technologies. The cascade pathway had the highest TCIE out of the three e-ethylene pathways for both current (92 gCO₂e/kWh) and future (124 gCO₂e/kWh) state of technologies. However, the carbon intensity of average US grid (i.e., 467 and 303 gCO₂e/kWh for current and future projections) were higher than the TCIEs of the corresponding timeline. Thus, reducing electricity requirement for e-ethylene pathways and bringing low-carbon generation mix in the United States (US) grid faster than the current projection are both essential to decarbonize ethylene and its downstream chemicals/polymers.

• 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. Bioenergy Technologies Office (BETO)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 2475290
• Alternate ID(s): OSTI ID: 2324679
• Journal Information: Journal of Cleaner Production, Journal Name: Journal of Cleaner Production Vol. 449; ISSN 0959-6526
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
CO2 utilization
cascade CO2 conversion
electrocatalytic reduction
ethene