Life-cycle assessment of a biogas power plant with application of different climate metrics and inclusion of near-term climate forcers. (15th December 2016)

• Record Type: Journal Article
• Authors: Iordan, Cristina; Lausselet, Carine; Cherubini, Francesco
• Is Part Of: Journal of environmental management. Volume 184:Part 3(2016)
• Page Start: 517
• Page End: 527
• Publication Date: 2016-12-15
• Subjects: Life cycle assessment (LCA) -- Biogas -- Climate metrics -- Near-term climate forcers (NTCFs) -- Global temperature change potential (GTP) -- Global warming potential (GWP); Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2016.10.030
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: This study assesses the environmental sustainability of electricity production through anaerobic co-digestion of sewage sludge and organic wastes. The analysis relies on primary data from a biogas plant, supplemented with data from the literature. The climate impact assessment includes emissions of near-term climate forcers (NTCFs) like ozone precursors and aerosols, which are frequently overlooked in Life Cycle Assessment (LCA), and the application of a suite of different emission metrics, based on either the Global Warming Potential (GWP) or the Global Temperature change Potential (GTP) with a time horizon (TH) of 20 or 100 years. The environmental performances of the biogas system are benchmarked against a conventional fossil fuel system. We also investigate the sensitivity of the system to critical parameters and provide five different scenarios in a sensitivity analysis. Hotspots are the management of the digestate (mainly due to the open storage) and methane (CH4 ) losses during the anaerobic co-digestion. Results are sensitive to the type of climate metric used. The impacts range from 52 up to 116 g CO2 -eq./MJ electricity when using GTP100 and GWP20, respectively. This difference is mostly due to the varying contribution from CH4 emissions. The influence of NTCFs is about 6% for GWP100 (worst case), and grows up to 31% for GWP20 (best case). The biogas system has a lower performance than the fossil reference system for the acidification and particulate matter formation potentials. We argue for an active consideration of NTCFs in LCA and a critical reflection over the climate metrics to be used, as these aspects can significantly affect the final outcomes. Highlights: LCA of a biogas system producing electricity from wastewaters in Norway. Climate impacts assessed using different emission metrics and including NTCFs. Results show the influence of different metrics on the climate impact categories. NTCFs contribute up to 30% of the impact if an integrated short-term metric is used. Hotspots are the management of the digestate and CH4 process losses.