Life Cycle Assessment of Bioenergy and Bio-Based Products from Perennial Grasses Cultivated on Marginal Land in the Mediterranean Region

Agricultural systems in the Mediterranean region are increasingly getting under pressure due to both global warming and the aggravating competition for agricultural land. Perennial grasses have the potential to tackle both challenges: they are drought-resistant crops and considered not to compete for high-productivity agricultural land because they can be grown on marginal land. This paper presents the outcome of a screening life cycle assessment (LCA) conducted as part of an integrated sustainability assessment within the EU-funded project ‘Optimization of Perennial Grasses for Biomass Production’ (OPTIMA). The project aims at optimised production of Miscanthus (Miscanthus × giganteus), giant reed (Arundo donax L.), switchgrass (Panicum virgatum L.) and cardoon (Cynara cardunculus L.) on marginal land in the Mediterranean region. Different cultivation and use options were investigated by comparing the entire life cycles of bioenergy and bio-based products to equivalent conventional products. The LCA results show that the cultivation of perennial grasses on marginal land and their use for stationary heat and power generation can achieve substantial greenhouse gas emission and non-renewable energy savings, with Miscanthus allowing for savings ranging up to 13 t CO2 eq./(ha · year) and 230 GJ/(ha · year), respectively. Negative environmental impacts are less pronounced. Significant parameters include irrigation needs and moisture content at harvest, which determines energy demand for technical drying. We conclude that the cultivation of perennial grasses on marginal land in the Mediterranean region provides potentials for climate change mitigation together with comparatively low other environmental impacts, if several boundary conditions and recommendations are met.