Large-scale bioenergy production from soybeans and switchgrass in Argentina Part B. Environmental and socio-economic impacts on a regional level

摘要

The feasibility of deploying a socio-economic and environmental impact analysis for large-scale bioenergy production on a regional level is analyzed, based on a set of defined criteria and indicators. The analysis is done for La Pampa province in Argentina. The case study results in conclusions in how far the criteria can be verified ex ante based on available methodologies and data sources. The impacts are analyzed for two bioenergy chains (soybeans and switchgrass) for a set of defined land use scenarios. The carbon stock change for switchgrass ranges from 0.2 to 1.2 ton C/ha/year and for soybean from -1.2 to 0 ton C/ha/year, depending on the scenario. The GHG emission reduction ranges from 88% to 133% for the switchgrass bioenergy chain (replacing coal or natural gas) and from 16% to 94% for the soybean bioenergy chain (replacing fossil fuel) for various lifetime periods. The annual soil loss, compared to the reference land use system is 2-10 ton/ha for the soybean bioenergy chain and 1-2 ton/ha for the switchgrass bioenergy chain. In total, nine sustainability principles are analyzed. In the case of switchgrass, most environmental benefits can be achieved when produced on suitable land of abandoned cropland. Soybean production for bioenergy shows a good overall sustainability performance if produced on abandoned cropland. The production of switchgrass on degraded grassland shows socio-economic and environmental benefits, which is not the case for soybean production. The production of bioenergy production on non-degraded grassland is not preferred. It is concluded that the scenario approach enables understanding of the complexity of the bioenergy chain and the underlying factors influencing the sustainability principles. It is difficult to give ex ante a final conclusion whether a bioenergy chain is sustainable or not as this depends not only on the previous land use system but also on other factors as the selection of the bioenergy crop, the suitable agroecological zone and the agricultural management system applied. The results also imply that it is possible to steer for a large part the sustainability performance of a bioenergy chain during project development and implementation. Land use planning plays a key role in this process.