Capturing uncertainty in GHG savings and carbon payback time of rapeseed oil displacing fossil diesel in Europe

Abstract

This article addresses different land use change scenarios, as well as uncertainty issues related to parameters and concerning how co-product credits are accounted for in the life-cycle modeling of rapeseed oil (RO). A comprehensive assessment of different land use change scenarios (rapeseed cultivation in former agricultural land and grassland) and agricultural practices has been conducted, which results in different carbon stock change values. RO GHG intensity and GHG emission implications when RO displaces petroleum diesel have been assessed in terms of probability distributions using a substitution method, three allocation approaches and ignoring co-product credits. The net GHG balance of rapeseed oil is strongly influenced by soil carbon stock variations due to land use change and by the magnitude of nitrous oxide emissions from cultivated soil. Depending on prior land use, GHG emissions may comply with the European renewable energy directive target of 35% GHG emission savings (arable land converted to rapeseed cultivation) or, conversely, may completely offset carbon gains attributed to rapeseed oil production for several decades (conversion of grassland).