One of the key points of contention over the climate benefit of biofuels is the impact of land use change (LUC) associated with biofuel feedstock production. LUC results in biogeochemical (e.g., soil organic carbon) and biogeophysical (e.g., surface albedo, evapotranspiration, and surface roughness) changes. Of the biogeophysical factors, surface albedo has been considered a dominant effect at the global scale.
A team at Argonne National Laboratory has now quantified land use change (LUC)-induced albedo effects for three major biofuels in the US, using satellite data products for albedo and vegetation observations. Published in the RSC journal Energy & Environmental Science, the analysis indicates that the land use change (LUC)-induced albedo effect is small for corn and miscanthus ethanol, but is significant for switchgrass ethanol, which is driven by the types, locations, and intensities of various land conversions to these biofuel feedstocks. . . .
With the LUC-induced albedo effect included, ethanol from corn, switchgrass, and miscanthus has life-cycle GHG emissions of 56, 29, and -4 g/MJ, respectively. These results translate to a GHG emission reduction of about 39%, 68%, and 104%, respectively, relative to petroleum-derived gasoline, which has a GHG emission intensity of 92 g CO2e/MJ. . . .