Development of Invasive Plants Control Approach through Pelletization of their Biomass to Produce Energy and Biochar

The aim of this study was to demonstrate the utilization of invasive plant materials a resource for energy production, applying pelletization and pellet pyrolysis, thus integrating plant eradication efforts with renewable energy solutions and valorization of plant biomass. The approach was demonstrated for three invasive plants – Japanese knotweed [Reynoutria japonica (Houtt.)], Jerusalem artichoke [Helianthus tuberosus (L.)], and Canadian goldenrod [Solidago canadensis (L.)] which are abundant in Northern Europe and elsewhere. As binder materials for pellet formation, sapropel and peat extraction residues were selected for their sustainability potential, as both represent organic waste materials that, similarly to invasive plant biomass, face a high likelihood of being disposed of without added value if not valorized. The calorific value of biomass plant pellets is comparable to values common for wood pellets and other plant materials, thus supporting their use for energy production. Pyrolysis provides possibilities to obtain biochar with increased specific surface area and higher caloric content, as well as application potential in agriculture. The studied invasive plant pellets do not contain elevated concentrations of heavy metals or other pollutants, thus supporting their application for the production of bioenergy or as a soil amendment.