Perennial Grass Species for Bioenergy Production: The State of the Art in Mechanical Harvesting

Future European strategies to reduce dependence on foreign markets for energy supply and energy production will rely on the further exploitation of the primary sector. Lignocellulosic feedstock for bioenergy production is a valuable candidate, and dedicated crops such as giant reed (Arundo donax L.), miscanthus (Miscanthus × giganteus), reed canary grass (Phalaris arundinacea L.), and switchgrass (Panicum virgatum L.) have been proven to be suitable for extensive cultivation on marginal lands. The present review aimed at providing a comprehensive picture of the mechanical strategies available for harvesting giant reed, miscanthus, reed canary grass, and switchgrass that are suitable for the possible upscaling of their supply chain. Since harvesting is the most impactful phase of a lignocellulosic supply chain in dedicated crops, the associated performance and costs were taken into account in order to provide concrete observations and suggestions for future implementation. The findings of the present review highlighted that the investigated species have a sufficient technology readiness level concerning mechanical harvesting for the upscaling of their cultivation. All the species could indeed be harvested with existing machinery, mostly derived from the context of haymaking, without compromising the work productivity.