Feasibility of usage of hemp as a feedstock for anaerobic digestion: Findings from a literature review of the relevant technological and energy dimensions

Abstract

Renewable biomasses are used worldwide as inputs for energy production through processes, like Anaerobic Digestion (AD), which is a well-established technology to transform them into bio-gas and other by-products. Maize, triticale, sunflower and sorghum are energy crops frequently used as feedstocks in AD applications, mainly because of their high biogas potential. However, their cultivation generates some negative environmental impacts due to the direct and indirect land use changes. Therefore, it is important to seek for alternative species to replace some of them with others with lower environmental impacts while producing comparable biogas and energy yields. Industrial Hemp (IH) was documented in this literature review to be a suitable crop for AD applications with yields that are highly competitive with those of the energy crops being used now. Additionally, this literature review provided insight into the diversity of the methane yielding parts of the IH plants, with fresh leaves yielding the highest quantities. Finally, the authors of this literature review highlighted the need for research and development designed to expand the usage of IH as green biomass in AD plants, for efficient production of biogas and organic nutrients, and thereby, contributing to transitioning toward low fossil-carbon footprint societies.

Graphical abstract

Keywords:

• Anaerobic digestion
• energy efficiency
• industrial hemp

Acknowledgements

Dr. Carlo Ingrao wishes to thank his coauthors for collaborating effectively in the design and development of the study, by providing valuable advice and by performing multiple step-by-step revisions of this manuscript. Additional thanks go to Dr. Francesca Valenti for being also the corresponding author of this paper. Furthermore, he thanks Prof. Donald Huisingh, for his key contributions in the study development, and for his multiple, in-depth revisions of this manuscript. Finally, the team of authors would like to thank: the Editor, Prof. Jörg Rinklebe, for kindly and promptly handling this paper submission; and the four anonymous experts for their constructive review work, that has contributed to improvement and upgrade of the manuscript.