Multiyear Life Cycle Assessment of switchgrass (Panicum virgatum L.) production in the Mediterranean region of Spain: A comparative case study

Abstract

An LCA of the cultivation of switchgrass in the Mediterranean region of Spain is carried out, based on 2010–2013 inventory data from experimental plots of two sites, Moncofar and Orihuela. Thus, a 4-year cycle is evaluated, considering different sources of variability. The functional unit is 1 t of switchgrass (dry basis) for electricity generation. Besides typical impact categories, blue and green water consumption impacts are also addressed by using watershed-specific characterization factors. In 2010, the production in Orihuela is more input-intensive than it is in Moncofar, while the biomass yield is lower. This causes greater climate change as CO2-eq. (709.1 vs. 65.0 kg t−1) and greater metal depletion as Fe-eq. (8.1 vs. 1.5 kg t−1). In the subsequent years, the yields are higher in Orihuela, and Moncofar performs worse for some specific impact categories, mainly the toxicity-related ones, and also metal depletion as Fe-eq., but only in 2011 (2.0 vs. 1.2 kg t−1). Due to larger irrigation doses, the blue water impact as ecosystem-eq. water is always higher in Orihuela (e.g. in 2010, 2020 vs. 390 m3 t−1). On the contrary, the green water impact, also as ecosystem-eq. water, is greater in Moncofar, except for the first year (86.8 vs. 15.2 m3 t−1). Switchgrass from the two locations could be eligible for bioelectricity production in the European Union in accordance with the sustainability requirements for greenhouse gas savings. Ad hoc decisions on crop management are, however, critical to the environmental impacts, evidencing the importance of taking a multi-year approach.