Comparative Life Cycle Evaluation of the Global Warming Potential (GWP) Impacts of Renewable Natural Gas Production Pathways

Journal Article · 01 June 2022 · Environmental Science and Technology

DOI: https://doi.org/10.1021/acs.est.2c00093 · OSTI ID:1889398

Rai, Srijana  ^[1]; Hage, Danny ^[1]; Littlefield, James ^[1]; Yanai, Gabrielle ^[1]; Skone, Timothy J. ^[1]

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1. National Energy Technology Lab. (NETL), Pittsburgh, PA (United States)

Renewable Natural Gas (RNG) sources are being considered in future energy strategy discussions as potential replacements for fossil natural gas (FNG). While today’s supply of RNG resources is insufficient to meet U.S. demands, there is significant interest in its viability to supplement and decarbonize the natural gas supply. However, the resources that compare the life cycle global warming potential (GWP) of various RNG production pathways are lacking and focus mostly on a singular pathway. This effort is an attempt to close this gap and provide a comparison between the life cycle GWP of three major RNG pathways and the FNG pathway. The three RNG pathways evaluated are Anaerobic Digestion (AD), Thermal Gasification (TG), and Power-to-Gas (P2G) using various feedstocks. The functional unit is 1MJ of compressed RNG ready for injection into the natural gas transmission network. The results show that RNG production is not always carbon neutral or negative. Depending on the pathway the GWP impact of RNG production can range from -229 to 27 g CO₂e/MJ compressed RNG, with AD of animal manure and AD of municipal solid waste being the least and the most impactful pathways, respectively, compared to the 10.1 g CO₂e/MJ impact for compressed FNG.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• OSTI ID: 1889398
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 12 Vol. 56; ISSN 0013-936X
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English