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Research article - Peer-reviewed, 2020

Including albedo in time-dependent LCA of bioenergy

Sieber, Petra; Ericsson, Niclas; Hammar, Torun; Hansson, Per-Anders

Abstract

Albedo change during feedstock production can substantially alter the life cycle climate impact of bioenergy. Life cycle assessment (LCA) studies have compared the effects of albedo and greenhouse gases (GHGs) based on global warming potential (GWP). However, using GWP leads to unequal weighting of climate forcers that act on different timescales. In this study, albedo was included in the time-dependent LCA, which accounts for the timing of emissions and their impacts. We employed field-measured albedo and life cycle emissions data along with time-dependent models of radiative transfer, biogenic carbon fluxes and nitrous oxide emissions from soil. Climate impacts were expressed as global mean surface temperature change over time ( increment T) and as GWP. The bioenergy system analysed was heat and power production from short-rotation willow grown on former fallow land in Sweden. We found a net cooling effect in terms of increment T per hectare (-3.8 x 10(-11) K in year 100) and GWP(100) per MJ fuel (-12.2 g CO(2)e), as a result of soil carbon sequestration via high inputs of carbon from willow roots and litter. Albedo was higher under willow than fallow, contributing to the cooling effect and accounting for 34% of GWP(100), 36% of increment T in year 50 and 6% of increment T in year 100. Albedo dominated the short-term temperature response (10-20 years) but became, in relative terms, less important over time, owing to accumulation of soil carbon under sustained production and the longer perturbation lifetime of GHGs. The timing of impacts was explicit with increment T, which improves the relevance of LCA results to climate targets. Our method can be used to quantify the first-order radiative effect of albedo change on the global climate and relate it to the climate impact of GHG emissions in LCA of bioenergy, alternative energy sources or land uses.

Keywords

albedo; bioenergy; climate impact; greenhouse gases; land use change; LCA; life cycle assessment; willow

Published in

GCB Bioenergy
2020, volume: 12, number: 6, pages: 410-425
Publisher: WILEY

Authors' information

Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology
Hammar, Torun
Swedish University of Agricultural Sciences, Department of Energy and Technology
Swedish University of Agricultural Sciences, Department of Energy and Technology

Sustainable Development Goals

SDG13 Climate action

UKÄ Subject classification

Bioenergy

Publication Identifiers

DOI: https://doi.org/10.1111/gcbb.12682

URI (permanent link to this page)

https://res.slu.se/id/publ/105342