Life cycle assessment of sunflower cultivation on abandoned mine land for biodiesel production

Producing biofuel feedstock on marginal lands is a viable way to offset fossil fuel production, global warming, and other adverse environmental impacts, while at the same time performing positive ecosystem services by reclaiming unused areas with value producing activities. This research study explored low-input production of sunflower biodiesel feedstock on abandoned mine land (AML) from coal mining refuse treated with bauxite residue (alkaline clay) through the lens of Life Cycle Assessment (LCA). An attributional LCA was conducted from the gate of an aluminum production facility (which produces the bauxite residue), through AML amelioration and low-input agricultural activities, to the gate of a biodiesel production facility. A 26 ha (ha) coal mine refuse pile located in Mather, PA, (91 km south of Pittsburgh), was used as an example location. Analysis of published agricultural data and greenhouse research led to a conservative sunflower oilseed yield of 500 kg/ha estimate, with a subsequent biodiesel yield of 190 kg/ha (217 l/ha). Results show substantial impact from the initial soil amendment process, however, when compared to complete restoration of the AML and other similar fuel production activities, overall environmental impacts over a twenty-year production cycle are sensible. An alternative allocation of the bauxite residue transport (i.e. associating transport impacts to aluminum industry) and addition of other fuel conversion pathways would show an improved energy return and better environmental outlook from biofuel production on AML.